Misplaced Pages

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85-600: Java Web Start was distributed as part of the Java Platform until being removed in Java SE 11, following its deprecation in Java SE 9. The code for Java Web Start was not released by Oracle as part of OpenJDK , and thus OpenJDK originally did not support it. IcedTea-Web provides an independent open source implementation of Java Web Start that is currently developed by the AdoptOpenJDK community, RedHat and Karakun AG , and which

170-428: A CPU-style MMU. Digital signal processors have similarly generalized over the years. Earlier designs used scratchpad memory fed by direct memory access , but modern DSPs such as Qualcomm Hexagon often include a very similar set of caches to a CPU (e.g. Modified Harvard architecture with shared L2, split L1 I-cache and D-cache). A memory management unit (MMU) that fetches page table entries from main memory has

255-547: A background process. To reduce the size of a Java Web Start application Sun Microsystems introduced a compression system called Pack200 in Java 1.5.0. It can compress a large jar file to one-ninth of its original size if it contains only Java classes. Java Web Start has supported Pack200 since it first appeared, but initially this feature required server-side cooperation and a certain amount of expertise to set up. When Sun introduced Java SE 6u10, Pack200 support became available without

340-473: A backing store. Memoization is an optimization technique that stores the results of resource-consuming function calls within a lookup table, allowing subsequent calls to reuse the stored results and avoid repeated computation. It is related to the dynamic programming algorithm design methodology, which can also be thought of as a means of caching. A content delivery network (CDN) is a network of distributed servers that deliver pages and other Web content to

425-524: A cache benefits one or both of latency and throughput ( bandwidth ). A larger resource incurs a significant latency for access – e.g. it can take hundreds of clock cycles for a modern 4 GHz processor to reach DRAM. This is mitigated by reading large chunks into the cache, in the hope that subsequent reads will be from nearby locations and can be read from the cache. Prediction or explicit prefetching can be used to guess where future reads will come from and make requests ahead of time; if done optimally,

510-424: A cache for frequently accessed data, providing high speed local access to frequently accessed data in the cloud storage service. Cloud storage gateways also provide additional benefits such as accessing cloud object storage through traditional file serving protocols as well as continued access to cached data during connectivity outages. The BIND DNS daemon caches a mapping of domain names to IP addresses , as does

595-613: A feature release every six months according to a strict, time-based model. Due to Oracle no longer releasing updates for long-term support (LTS) releases under a permissive license, other organizations have begun to publish their own builds, both in regular and long-term support terms. Many Linux distributions offer their own builds through their package manager , including Microsoft Windows . In order to bundle OpenJDK in Fedora and other free Linux distributions, OpenJDK needed to be buildable using only free software components. Due to

680-473: A resolver library. Write-through operation is common when operating over unreliable networks (like an Ethernet LAN), because of the enormous complexity of the coherency protocol required between multiple write-back caches when communication is unreliable. For instance, web page caches and client-side network file system caches (like those in NFS or SMB ) are typically read-only or write-through specifically to keep

765-729: A separate frame. Web Start can also launch unmodified applets that are packaged inside .jar files, by writing the appropriate JNLP file. This file can also pass the applet parameters. Such applets also run in a separate frame. Applet launcher may not support some specific cases like loading class as resource. Like applets, Java Web Start is cross-platform . With JDK9 , several deployment technologies including applets and Java Web Start were deprecated by Oracle. In March 2018, Oracle announced it will not include Java Web Start in Java SE 11 (18.9 LTS) and later. Developers will need to transition to other deployment technologies. A few stand-alone alternatives have since arisen. The developer prepares

850-470: A set of rules defining how exactly to implement the launching mechanism. JNLP files include information such as the location of the jar package file and the name of the main class for the application, in addition to any other parameters for the program. A properly configured browser passes JNLP files to a Java Runtime Environment (JRE) which in turn downloads the application onto the user's machine and starts executing it. The development of JNLP took place under

935-423: A special XML file with JNLP extension. This file describes the application requirements, code location, parameters and additional permissions (if any). The browser downloads this file as any other and (following its MIME type , application/x-java-jnlp-file ) opens it with Web Start tool. Web Start tool downloads all necessary resources and launches the application. Java Web Start provides a series of classes in

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1020-460: A specialized cache, used for recording the results of virtual address to physical address translations. This specialized cache is called a translation lookaside buffer (TLB). Information-centric networking (ICN) is an approach to evolve the Internet infrastructure away from a host-centric paradigm, based on perpetual connectivity and the end-to-end principle , to a network architecture in which

1105-499: A specific function are the D-cache , I-cache and the translation lookaside buffer for the memory management unit (MMU). Earlier graphics processing units (GPUs) often had limited read-only texture caches and used swizzling to improve 2D locality of reference . Cache misses would drastically affect performance, e.g. if mipmapping was not used. Caching was important to leverage 32-bit (and wider) transfers for texture data that

1190-451: A system writes data to cache, it must at some point write that data to the backing store as well. The timing of this write is controlled by what is known as the write policy . There are two basic writing approaches: A write-back cache is more complex to implement since it needs to track which of its locations have been written over and mark them as dirty for later writing to the backing store. The data in these locations are written back to

1275-456: A tag matching that of the desired data, the data in the entry is used instead. This situation is known as a cache hit . For example, a web browser program might check its local cache on disk to see if it has a local copy of the contents of a web page at a particular URL . In this example, the URL is the tag, and the content of the web page is the data. The percentage of accesses that result in cache hits

1360-410: A user, based on the geographic locations of the user, the origin of the web page and the content delivery server. CDNs began in the late 1990s as a way to speed up the delivery of static content, such as HTML pages, images and videos. By replicating content on multiple servers around the world and delivering it to users based on their location, CDNs can significantly improve the speed and availability of

1445-476: A webserver, which replies with a JNLP file (instead of a HTML file) for the application. The JNLP client parses this file, requests the resources specified (jar files), waits for the retrieval of all required resources, and then launches the application. The JNLP file can list resources as "lazy", which informs the JNLP client that the application does not need those resources to start, but can retrieve them later on when/if

1530-489: A website or application. When a user requests a piece of content, the CDN will check to see if it has a copy of the content in its cache. If it does, the CDN will deliver the content to the user from the cache. A cloud storage gateway, also known as an edge filer, is a hybrid cloud storage device that connects a local network to one or more cloud storage services , typically object storage services such as Amazon S3 . It provides

1615-401: Is a variant of LRU designed for the situation where the stored contents in cache have a valid lifetime. The algorithm is suitable in network cache applications, such as ICN, content delivery networks (CDNs) and distributed networks in general. TLRU introduces a new term: time to use (TTU). TTU is a time stamp on content which stipulates the usability time for the content based on the locality of

1700-435: Is a web cache that is shared among all users of that network. Another form of cache is P2P caching , where the files most sought for by peer-to-peer applications are stored in an ISP cache to accelerate P2P transfers. Similarly, decentralised equivalents exist, which allow communities to perform the same task for P2P traffic, for example, Corelli. A cache can store data that is computed on demand rather than retrieved from

1785-482: Is an example of disk cache, is managed by the operating system kernel . While the disk buffer , which is an integrated part of the hard disk drive or solid state drive, is sometimes misleadingly referred to as "disk cache", its main functions are write sequencing and read prefetching. Repeated cache hits are relatively rare, due to the small size of the buffer in comparison to the drive's capacity. However, high-end disk controllers often have their own on-board cache of

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1870-405: Is bundled in some OpenJDK installers. Next to this OpenWebStart provides an open source based implementation that is based on IcedTea-Web but offers more features and commercial support options. Unlike Java applets , Web Start applications do not run inside the browser. By default they run in the same sandbox as applets, with several minor extensions like allowing to load and save the file that

1955-413: Is explicitly selected by the user through the file selection dialog. Only signed applications can be configured to have additional permissions. Web Start has an advantage over applets in that it overcomes many compatibility problems with browsers' Java plugins and different JVM versions. Web Start programs are no longer an integrated part of the web page, they are independent applications that run in

2040-435: Is known as the hit rate or hit ratio of the cache. The alternative situation, when the cache is checked and found not to contain any entry with the desired tag, is known as a cache miss . This requires a more expensive access of data from the backing store. Once the requested data is retrieved, it is typically copied into the cache, ready for the next access. During a cache miss, some other previously existing cache entry

2125-428: Is made up of a pool of entries. Each entry has associated data , which is a copy of the same data in some backing store . Each entry also has a tag , which specifies the identity of the data in the backing store of which the entry is a copy. When the cache client (a CPU, web browser, operating system ) needs to access data presumed to exist in the backing store, it first checks the cache. If an entry can be found with

2210-409: Is read or written for the first time is effectively being buffered; and in the case of a write, mostly realizing a performance increase for the application from where the write originated. Additionally, the portion of a caching protocol where individual writes are deferred to a batch of writes is a form of buffering. The portion of a caching protocol where individual reads are deferred to a batch of reads

2295-476: Is requested that is stored near data that has already been requested. In memory design, there is an inherent trade-off between capacity and speed because larger capacity implies larger size and thus greater physical distances for signals to travel causing propagation delays . There is also a tradeoff between high-performance technologies such as SRAM and cheaper, easily mass-produced commodities such as DRAM , flash , or hard disks . The buffering provided by

2380-413: Is typically removed in order to make room for the newly retrieved data. The heuristic used to select the entry to replace is known as the replacement policy . One popular replacement policy, least recently used (LRU), replaces the oldest entry, the entry that was accessed less recently than any other entry. More sophisticated caching algorithms also take into account the frequency of use of entries. When

2465-519: The jarsigner tool that comes with the JDK . The open-source IcedTea project provides an alternative JNLP implementation in IcedTea-Web . As of version 1.7.2, it also works on newer versions without official JWS support. To run Java Web Start-based application after the release of Java 11, the company Karakun AG has released the open source tool OpenWebStart , based on IcedTea-Web. The tool includes all

2550-734: The Fedora 9 and Ubuntu 8.04 distributions included IcedTea 6, based completely on free and open source code. Fedora 9 was the first version to be shipped with IcedTea6, based on the OpenJDK6 sources from Sun rather than OpenJDK7. It was also the first to use OpenJDK for the package name (via the OpenJDK trademark agreement ) instead of IcedTea. Ubuntu also first packaged IcedTea7 before later moving to IcedTea6. Packages for IcedTea6 were also created for Debian and included in Lenny . On July 12, 2008, Debian accepted OpenJDK-6 in unstable, and it later

2635-696: The IcedTea-Web project. In 2020, a port of OpenJDK 8 to OpenVMS on the Itanium platform was released. The number of external contributions to OpenJDK is growing since project inception. OpenJDK 11, released in September 2018, received 20% of external fixes and brought 17 new JEPs (features), out of which 3 were contributed by the community. Namely, JEP 315: "Improve Aarch64 Intrinsics" (contributed by BellSoft ), JEP 318: "Epsilon: A No-Op Garbage Collector" (by Red Hat) and JEP 331: "Low-Overhead Heap Profiling" (contributed by Google). On October 11, 2010, IBM , by far

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2720-528: The Java Community Process as JSR 56. It includes the original 1.0 release, the subsequent 1.5 maintenance release, and as of 2006, the pending 6.0 maintenance release. Important Web Start features include the ability to automatically download and install a JRE in the case where the user does not have Java installed, and for programmers to specify which JRE version a given program needs in order to execute. The user does not have to remain connected to

2805-591: The encumbered components in the class library and implicit assumptions within the build system that the JDK being used to build OpenJDK was a Sun JDK, this was not possible. To achieve openness, Red Hat started the IcedTea project in June 2007. It began life as an OpenJDK/ GNU Classpath hybrid that could be used to bootstrap OpenJDK, replacing the encumbrances with code from GNU Classpath. On November 5, 2007, Red Hat signed both

2890-500: The page cache associated with a prefetcher or the web cache associated with link prefetching . Small memories on or close to the CPU can operate faster than the much larger main memory . Most CPUs since the 1980s have used one or more caches, sometimes in cascaded levels ; modern high-end embedded , desktop and server microprocessors may have as many as six types of cache (between levels and functions). Some examples of caches with

2975-468: The GPL by March 2007, "except for a few components that Sun does not have the right to publish in source form under the GPL". According to free-software advocate Richard Stallman , this would end the "Java trap", the vendor lock-in that he argues applied to Java and programs written in Java. Following their promise to release a Java Development Kit (JDK) based almost completely on free and open-source code in

3060-505: The Internet to execute the downloaded programs, because they execute from a locally maintained cache . Updates of the software download from the Web and become available when the user has a connection to the Internet, thus easing the burden of deployment. Any computer user can use JNLP simply by installing a JNLP client (most commonly Java Web Start). The installation can occur automatically such that

3145-526: The OpenJDK project and has several project committers on staff. Red Hat resigned leadership of OpenJDK 6 at the beginning of 2017 and this was then taken up by Azul Systems. Since April 2016 there are unsupported community builds of OpenJDK for Microsoft Windows on GitHub in the project ojdkbuild which are released in pace with updates for Oracle JDK. From build 8u151 on, the MSI-installer offers an optional component for using Java Web Start based on

3230-487: The OpenJDK project for Mac OS X. Apple will contribute most of the key components, tools and technology required for a Java SE 7 implementation on Mac OS X, including a 32-bit and 64-bit HotSpot-based Java virtual machine, class libraries, a networking stack and the foundation for a new graphical client. On January 11, 2011, the Mac OS X Port Project was created on OpenJDK, and Apple made the first public contribution of code to

3315-665: The Oracle OpenWorld conference, Jonathan Schwartz said that the company intended to announce the open-sourcing of the core Java Platform within 30 to 60 days. Sun released the Java HotSpot virtual machine and compiler as free software under the GNU General Public License on November 13, 2006, with a promise that the rest of the JDK (which includes the Java Runtime Environment ) would be placed under

3400-662: The Porters Group. As of January 2008, both are part of the mailing list discussions. Another project pending formalization on the Porters Group is the Haiku Java Team led by Bryan Varner. In December 2007, Sun moved the revision control of OpenJDK from TeamWare to Mercurial (and later to Git and GitHub ), as part of the process of releasing it to open-source communities. OpenJDK has comparatively strict procedures of accepting code contributions: every proposed contribution must be reviewed by another OpenJDK committer and

3485-606: The Sun Contributor Agreement and the OpenJDK Community TCK License. One of the first benefits of this agreement is tighter alignment with the IcedTea project, which brings together Fedora , the Linux distribution, and JBoss , the application server, technologies in a Linux environment. IcedTea provided free software alternatives for the few remaining proprietary sections in the OpenJDK project. In May 2008,

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3570-418: The amount of information that needs to be transmitted across the network, as information previously stored in the cache can often be re-used. This reduces bandwidth and processing requirements of the web server, and helps to improve responsiveness for users of the web. Web browsers employ a built-in web cache, but some Internet service providers (ISPs) or organizations also use a caching proxy server, which

3655-414: The application requests them. The example below gives a simple JNLP file to launch the applet, specifying code base, source, main class and window size. Such file contains all necessary references and is self-sufficient to launch the application. As no permissions are requested, the code will run in a sandbox. JNLP also states that this application can run offline (if already cached) and should be updated as

3740-409: The backing store only when they are evicted from the cache, a process referred to as a lazy write . For this reason, a read miss in a write-back cache will often require two memory backing store accesses to service: one for the write back, and one to retrieve the needed data. Other policies may also trigger data write-back. The client may make many changes to data in the cache, and then explicitly notify

3825-620: The biggest participant in the Apache Harmony project, decided to join Oracle on the OpenJDK project, effectively shifting its efforts from Harmony to OpenJDK. Bob Sutor, IBM's head of Linux and open source, blogged that "IBM will be shifting its development effort from the Apache Project Harmony to OpenJDK". On November 12, 2010, Apple Inc. (just three weeks after deprecating its own Java runtime port ) and Oracle Corporation announced

3910-486: The cache ahead of time. Anticipatory paging is especially helpful when the backing store has a long latency to read the first chunk and much shorter times to sequentially read the next few chunks, such as disk storage and DRAM. A few operating systems go further with a loader that always pre-loads the entire executable into RAM. A few caches go even further, not only pre-loading an entire file, but also starting to load other related files that may soon be requested, such as

3995-448: The cache is a network-level solution. Therefore, it has rapidly changing cache states and higher request arrival rates; moreover, smaller cache sizes impose different requirements on the content eviction policies. In particular, eviction policies for ICN should be fast and lightweight. Various cache replication and eviction schemes for different ICN architectures and applications have been proposed. The time aware least recently used (TLRU)

4080-452: The cache is divided into two partitions called privileged and unprivileged partitions. The privileged partition can be seen as a protected partition. If content is highly popular, it is pushed into the privileged partition. Replacement of the privileged partition is done by first evicting content from the unprivileged partition, then pushing content from the privileged partition to the unprivileged partition, and finally inserting new content into

4165-404: The cache to write back the data. Since no data is returned to the requester on write operations, a decision needs to be made whether or not data would be loaded into the cache on write misses. Both write-through and write-back policies can use either of these write-miss policies, but usually they are paired. Entities other than the cache may change the data in the backing store, in which case

4250-400: The cache, the faster the system performs. To be cost-effective, caches must be relatively small. Nevertheless, caches are effective in many areas of computing because typical computer applications access data with a high degree of locality of reference . Such access patterns exhibit temporal locality, where data is requested that has been recently requested, and spatial locality, where data

4335-612: The company was acquired by Oracle Corporation . The implementation is licensed under the GNU General Public License 2 with a linking exception , preventing components that linked to the Java Class Library becoming subject to the terms of the GPL license. OpenJDK is the official reference implementation of Java SE since version 7, and is the most popular distribution of the JDK. Sun announced in JavaOne 2006 that Java would become open-source software, and on October 25, 2006, at

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4420-487: The compatibility tests in the Java SE 6 TCK . Since August 2008, OpenJDK 7 is usable on macOS and other BSD variants. On Android Nougat , OpenJDK replaced the now-discontinued Apache Harmony as the Java libraries in the source code of the mobile operating system . Google was in a legal dispute with Oracle over claims of copyright and patent infringement through its use of re-implementations of copyrighted Java APIs via Harmony. While also stating that this change

4505-510: The content and information from the content publisher. Owing to this locality-based time stamp, TTU provides more control to the local administrator to regulate in-network storage. In the TLRU algorithm, when a piece of content arrives, a cache node calculates the local TTU value based on the TTU value assigned by the content publisher. The local TTU value is calculated by using a locally-defined function. Once

4590-589: The contributor must have signed the Sun/Oracle Contributor Agreement (SCA/OCA). Preferably, there should also be a jtreg test demonstrating the bug has been fixed. Initially, the external patch submission process was slow and, until September 2008, commits to the codebase were only made by Sun engineers. The process has improved and, as of 2010 , simple patches and backports from OpenJDK 7 to OpenJDK 6 can take place within hours rather than days. In 2011, an unofficial port of OpenJDK 6.0 to OS/2

4675-525: The copy in the cache may become out-of-date or stale . Alternatively, when the client updates the data in the cache, copies of those data in other caches will become stale. Communication protocols between the cache managers that keep the data consistent are associated with cache coherence . On a cache read miss, caches with a demand paging policy read the minimum amount from the backing store. A typical demand-paging virtual memory implementation reads one page of virtual memory (often 4 KB) from disk into

4760-415: The data item to its residing storage at a later stage or else occurring as a background process. Contrary to strict buffering, a caching process must adhere to a (potentially distributed) cache coherency protocol in order to maintain consistency between the cache's intermediate storage and the location where the data resides. Buffering, on the other hand, With typical caching implementations, a data item that

4845-408: The data item to realize a performance increase by virtue of being able to be fetched from the cache's (faster) intermediate storage rather than the data's residing location. With write caches, a performance increase of writing a data item may be realized upon the first write of the data item by virtue of the data item immediately being stored in the cache's intermediate storage, deferring the transfer of

4930-403: The data stored in a cache might be the result of an earlier computation or a copy of data stored elsewhere. A cache hit occurs when the requested data can be found in a cache, while a cache miss occurs when it cannot. Cache hits are served by reading data from the cache, which is faster than recomputing a result or reading from a slower data store; thus, the more requests that can be served from

5015-562: The disk cache in RAM. A typical CPU reads a single L2 cache line of 128 bytes from DRAM into the L2 cache, and a single L1 cache line of 64 bytes from the L2 cache into the L1 cache. Caches with a prefetch input queue or more general anticipatory paging policy go further—they not only read the data requested, but guess that the next chunk or two of data will soon be required, and so prefetch that data into

5100-426: The end-user sees the client launcher downloading and installing the Java application when first executed. JNLP works in a similar fashion to how HTTP/HTML works for the web. For rendering an HTML webpage , after the user clicks on a weblink, the browser submits a URL to a webserver , which replies with an HTML file. The browser then requests the resources referred to by this file (images, css ), and finally renders

5185-464: The first half of 2007, Sun released the complete source code of the Java Class Library under the GPL on May 8, 2007, except for some limited parts that had been licensed to Sun by third parties and Sun was unable to re-license under the GPL. Included in the list of encumbered parts were several major components of the Java graphical user interface (GUI). Sun stated that it planned to replace

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5270-447: The focal point is identified information. Due to the inherent caching capability of the nodes in an ICN, it can be viewed as a loosely connected network of caches, which has unique requirements for caching policies. However, ubiquitous content caching introduces the challenge to content protection against unauthorized access, which requires extra care and solutions. Unlike proxy servers, in ICN

5355-485: The functionality of IcedTea-Web and adds extended features, such as native installers for Mac OS, Windows, and Linux. IcedTea-Web was created with support from RedHat and AdoptOpenJDK . OpenJDK OpenJDK ( Open Java Development Kit ) is a free and open-source implementation of the Java Platform, Standard Edition (Java SE). It is the result of an effort Sun Microsystems began in 2006, four years before

5440-645: The hard disk drive's data blocks. Finally, a fast local hard disk drive can also cache information held on even slower data storage devices, such as remote servers (web cache) or local tape drives or optical jukeboxes ; such a scheme is the main concept of hierarchical storage management . Also, fast flash-based solid-state drives (SSDs) can be used as caches for slower rotational-media hard disk drives, working together as hybrid drives or solid-state hybrid drives (SSHDs). Web browsers and web proxy servers employ web caches to store previous responses from web servers, such as web pages and images . Web caches reduce

5525-461: The javax.jnlp package which provide various services to the application. Sun designed most of these services with the aim of allowing carefully controlled access to resources (such as files and the system clipboard) while restricting the application to authorized operations. Sun introduced version 1.0 of Web Start in March 2001, while 64-bit Windows support was added only in Java 6 (later than 64-bit Java

5610-621: The latency is bypassed altogether. The use of a cache also allows for higher throughput from the underlying resource, by assembling multiple fine-grain transfers into larger, more efficient requests. In the case of DRAM circuits, the additional throughput may be gained by using a wider data bus. Hardware implements cache as a block of memory for temporary storage of data likely to be used again. Central processing units (CPUs), solid-state drives (SSDs) and hard disk drives (HDDs) frequently include hardware-based cache, while web browsers and web servers commonly rely on software caching. A cache

5695-456: The local TTU value is calculated the replacement of content is performed on a subset of the total content stored in cache node. The TLRU ensures that less popular and short-lived content should be replaced with incoming content. The least frequent recently used (LFRU) cache replacement scheme combines the benefits of LFU and LRU schemes. LFRU is suitable for network cache applications, such as ICN, CDNs and distributed networks in general. In LFRU,

5780-452: The need for special server support. Application designers can enable or disable this feature within JNLP files. On slow connections Pack200 gives a performance boost in application startup time and download time. By default, Java Web Start applications run "restricted", which means that they do not have access to some system resources such as local files. But publishers can remove these restrictions by signing their Web Start applications with

5865-417: The network protocol simple and reliable. Search engines also frequently make web pages they have indexed available from their cache. For example, Google provides a "Cached" link next to each search result. This can prove useful when web pages from a web server are temporarily or permanently inaccessible. Database caching can substantially improve the throughput of database applications, for example in

5950-402: The page once it has received enough information. Page rendering usually starts before all resources have downloaded; some resources not critical to the layout of the page (such as images) can follow on afterwards. JNLP mirrors this process; in the same way that a Web browser renders a webpage, a JNLP client "renders" a Java app . After the user clicks on a weblink, the browser submits a URL to

6035-528: The privileged partition. In the above procedure, the LRU is used for the privileged partition and an approximated LFU (ALFU) scheme is used for the unprivileged partition. The basic idea is to cache the locally popular content with the ALFU scheme and push the popular content to the privileged partition. In 2011, the use of smartphones with weather forecasting options was overly taxing AccuWeather servers; two requests within

6120-499: The process of caching and the process of buffering. Fundamentally, caching realizes a performance increase for transfers of data that is being repeatedly transferred. While a caching system may realize a performance increase upon the initial (typically write) transfer of a data item, this performance increase is due to buffering occurring within the caching system. With read caches, a data item must have been fetched from its residing location at least once in order for subsequent reads of

6205-412: The processing of indexes , data dictionaries , and frequently used subsets of data. A distributed cache uses networked hosts to provide scalability, reliability and performance to the application. The hosts can be co-located or spread over different geographical regions. The semantics of a "buffer" and a "cache" are not totally different; even so, there are fundamental differences in intent between

6290-872: The project. The initial Apple contribution built on the OpenJDK BSD port. In July 2011, SAP AG announced that SAP officially joined the OpenJDK project. The OpenJDK project produces a number of components: most importantly the virtual machine ( HotSpot ), the Java Class Library and the Java compiler ( javac ). The Web browser plugin and Web Start , which form part of Oracle Java , are not included in OpenJDK. Sun previously indicated that they would try to open-source these components, but neither Sun nor Oracle Corporation have done so. The only currently available free plugin and Web Start implementations as of 2016 are those provided by IcedTea . OpenJDK 9+ supports AOT compilation ( jaotc ) using GraalVM (JEP 295). The experimental -XX:+EnableJVMCIProduct flag enables

6375-537: The remaining proprietary components with alternative implementations and to make the class library completely free. When initially released in May 2007, 4% of the OpenJDK class library remained proprietary. By the appearance of OpenJDK 6 in May 2008, less than 1% (the SNMP implementation, which is not part of the Java specification) remained, making it possible to build OpenJDK without any binary plugs. The binary plug requirement

6460-457: The same park would generate separate requests. An optimization by edge-servers to truncate the GPS coordinates to fewer decimal places meant that the cached results from the earlier query would be used. The number of to-the-server lookups per day dropped by half. While CPU caches are generally managed entirely by hardware, a variety of software manages other caches. The page cache in main memory, which

6545-662: The test suite that determines whether a project based on OpenJDK complies with the Java SE 6 specification). Also in November 2007, the Porters Group was created on OpenJDK to aid in efforts to port OpenJDK to different processor architectures and operating systems . The BSD porting project led by Kurt Miller and Greg Lewis and the Mac OS X porting project (based on the BSD one) led by Landon Fuller have expressed interest in joining OpenJDK via

6630-544: The use of Graal JIT (JEP 317). OpenJDK was initially based only on the JDK 7 version of the Java platform. Since JDK 10, the effort to produce an open-source reference implementation of the Java SE Platform was moved over to the JDK Project. Unlike past JDK Release Projects, which produced just one feature release and then terminated, this long-running project will produce all future JDK feature releases and will ship

6715-407: The whole JDK open sourced and the binary plugs not necessary anymore. On November 5, 2007, Red Hat announced an agreement with Sun, signing Sun's broad contributor agreement (which covers participation in all Sun-led free and open-source software projects by all Red Hat engineers) and Sun's OpenJDK Community Technology Compatibility Kit (TCK) License Agreement (which gives the company access to

6800-503: Was first available). Since J2SE 1.4 Web Start comes as a default part of Java Runtime Environment (JRE) called javaws , computer administrators no longer have to install it separately. Programmers often speak of the Java Network Launching Protocol ( JNLP ) interchangeably with the term "Web Start". The JNLP protocol, defined with an XML schema , specifies how to launch Java Web Start applications. JNLP consists of

6885-636: Was first released. This port is included in the OS/2 derivative ArcaOS . On 25 September 2013, Microsoft and Azul Systems collaborated to create Zulu, a build of OpenJDK for users of the Windows Azure cloud. Zulu is available as a free download from the community site Zulu.org . It is also possible to get Zulu on Amazon Web Services via Canonical's Juju Charm Store, the Docker Hub, and Azul Systems repositories. Azul contributes bug fixes and enhancements back to

6970-505: Was included in stable . OpenJDK is also available on openSUSE , Red Hat Enterprise Linux and RHEL derivatives such as CentOS . In June 2008, Red Hat announced that the packaged binaries for OpenJDK on Fedora 9 , built using IcedTea 6, had passed the Technology Compatibility Kit tests and could claim to be a fully compatible Java 6 implementation. In July 2009, an IcedTea 6 binary build for Ubuntu 9.04 passed all of

7055-503: Was later dropped from OpenJDK 7 as part of b53 in April 2009. This was made possible, over the course of the first year, by the work of Sun Microsystems and the OpenJDK community. Each encumbrance was either released as free and open-source software or replaced with an alternative. Beginning in December 2010, all the so-called binary plugs were replaced by open-source replacements, making

7140-449: Was often as little as 4 bits per pixel. As GPUs advanced, supporting general-purpose computing on graphics processing units and compute kernels , they have developed progressively larger and increasingly general caches, including instruction caches for shaders , exhibiting functionality commonly found in CPU caches. These caches have grown to handle synchronization primitives between threads and atomic operations , and interface with

7225-464: Was to create a more consistent platform between Java on Android and other platforms, the company admitted that the switch was motivated by the lawsuit, arguing that Oracle had authorized its use of the OpenJDK code by licensing it under the GPL. Cache (computing) In computing , a cache ( / k æ ʃ / KASH ) is a hardware or software component that stores data so that future requests for that data can be served faster;

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