Java Glossary : JRE

Java definitions: 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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Java Runtime Environment. This is the subset of Sun's Java Development Kit JDK/SDK that you can ship with your application.

Version	Executable	Notes
JRE 1.4.2_04	Download ( 10 mb ) Look in the JRE column, past the Netbeans stuff, lower on the page under 32-bit/64-bit for Windows/Linux/Solaris SPARC 32-bit for Solaris x86.	It includes the Java Plug-in and Java Webstart. It includes the JVM and the standard class library files, but no source, and no javac.exe. It does not include JavaMail or JAF.
JRE 1.4.1_03 (old)	Download ( 10 mb ) Look in the JRE column.	It now includes the Java Plug-in. It includes the JVM and the standard class library files, but no source, and no javac.exe.
JRE 1.3.1 (old)	Download	It now includes the Java Plug-in. It includes the JVM and the standard class library files, but no source, and no javac.exe .
JRE 1.2 (old)	Download	It includes the JVM and the standard class library files, but no source, and no javac.exe . The java.exe file it contains is renamed to jre.exe .
Everything on CD	sign up: to have a free CD of the latest Java software mailed to you on CD.	This provides a convenient disk to copy to give to others without high speed internet. It provides backup for you, especially of old versions Sun may stop posting. A new CD will arrive every quarter.

You might want to manually set your JAVA_HOME environment variable to the JRE directory e.g. C:\Program Files\Java\j2re1.4.2_04. Some software finds Java using this variable rather than poking around in the registry.

Testing

Test your JRE by typing in a DOS box:
```
java.exe -version
```
You should see the expected version you just installed, probably 1.4.2_04. It can be problematic to have more than one version installed at a time.
Test your JRE browser's ability to run Applets by running wassup. It should tell you that your browser is using the JVM version you just installed, probably 1.4.2_04. Look for the line marked java.version. If wassup does not run, or you have the wrong version, go into Settings | Control Panel | Java Plug-In | Browser and turn off each browser, then click apply, then turn them on again, then hit apply again. Then retest with wassup. If that still does not work, turn on the Java console, try wassup again and look for clues.
Test Java Web Start by typing javaws.exe and running any sample application.
Check that the associations for the *.jnlp extension is set to point to the appropriate javaws.exe and *.jar is set to point to javaw.exe. Confirm this in any My Computer directory display with tools | folder options | file types.
Check the Opera browser's quick prefereneces to make sure you have Java enabled. Turn on the console with tools | advanced | Java console to get some hints why it may not be working. Make sure Opera has *.jnlp files associated with mime type application-x-java-jnlp-file in preferences | files.

failed installs ¤ flipping between different JVMs ¤ java.exe ¤ JDK ¤ old JREs

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