Java se development kit 7 update 3 software#
It is also the foundation for the technologies in the Java 2 Platform, Enterprise Edition (J2EE) for enterprise software development and deployment. In addition, two key deployment technologies are part of the JRE: Java Plug-in, which enables applets to run in popular browsers and Java Web Start, which deploys standalone applications over a network. The Java Runtime Environment (JRE) provides the libraries, the Java Virtual Machine, and other components to run applets and applications written in the Java programming language. To explain the difference between JDK and JRE, the best is to read the Oracle documentation and consult the diagram :
Indeed there are specific implementations of the JVM for different systems (Windows, Linux, MacOS, see the wikipedia list.), the aim is that with the same bytecodes they all give the same results. It's also the entity that allows Java to be a "portable language" (write once, run anywhere). The JVM doesn't understand Java source code, that's why you compile your *.java files to obtain *.class files that contain the bytecodes understandable by the JVM. The Java Virtual Machine (JVM) is the virtual machine that run the Java bytecodes. In other words if you are a Java programmer you will need JDK in your system and this package will include JRE and JVM as well but if you are normal user who like to play online games then you will only need JRE and this package will not have JDK in it. JVM = Class loader system + runtime data area + Execution Engine. JRE = JVM + Java Packages Classes(like util, math, lang, awt,swing etc)+runtime libraries. In layman terms: JDK is grandfather JRE is father and JVM is their son. These files allow the standard library to be used with jlink. jmods/, which holds JMOD files for the standard library, has been added.The most important of them is javac others include jar, javadoc and jshell. bin/ has been enlarged with development tools.It is a superset of the JRE, with some additions: so (Linux) files under bin/ or lib/ with supporting, system-specific native binary code. At a certain level, the Java standard library needs to call into native code.class files of the Java standard library. The most important is modules, a file that contains the. jars, configuration files, property files, fonts, translations, certs, etc. lib/ has a large number of supporting files: some.conf/ holds user-editable configuration files for Java experts to play with.There are some other utilities here as well, such as keytool and policytool. The most important is java (and for Windows, javaw as well), which launches the JVM. bin/ contains Java's executable programs.It's basically a bunch of directories with Java-related files, to wit: The JRE is, as the name implies, an environment. The answer above (by Pablo) is very right. Why would you need the JDK then? Because the application server will convert JSP into Java servlets and needs to use the JDK to compile the servlets. For example, if you are deploying a web application with JSP, you are technically just running Java programs inside the application server. Sometimes, even if you are not planning to do any Java development on a computer, you still need the JDK installed.
Java se development kit 7 update 3 install#
On the other hand, if you are planning to do some Java programming, you need to install the JDK instead. Usually, if you only care about running Java programs on computer you will only install the JRE. It is capable of creating and compiling programs. It has everything the JRE has, but also the compiler ( javac) and tools (like javadoc and jdb). The JDK is the Java Development Kit, the full-featured SDK for Java. However, it cannot be used to create new programs. It is a package of everything necessary to run a compiled Java program, including the Java Virtual Machine (JVM), the Java Class Library, the java command, and other infrastructure.
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