Eclipse and java home

Overview

Eclipse startup is controlled by the options in $ECLIPSE_HOME/eclipse.ini . If $ECLIPSE_HOME is not defined, the default eclipse.ini in your Eclipse installation directory (or in the case of Mac, the Eclipse.app/Contents/MacOS directory) is used.

eclipse.ini is a text file containing command-line options that are added to the command line used when Eclipse is started up. There are many options available, please see here.

1. You can, and should, experiment with changes to the launch command from your Command Prompt/Terminal before changing the eclipse.ini itself.
2. Each option and each argument to an option must be on its own line.
3. All lines after -vmargs are passed as arguments to the JVM, so all arguments and options for eclipse must be specified before -vmargs (just like when you use arguments on the command-line)
4. Any use of -vmargs on the command-line replaces all -vmargs settings in the .ini file unless —launcher.appendVmargs is specified either in the .ini file or on the command-line. (doc)
5. -XX VM arguments are subject to change without notice, even during minor updates. If the JVM keeps exiting with code 2 instead of starting Eclipse, try removing them.
6. Make a backup—keep a copy of the original contents on hand so you don’t break your installation and have to download it all again.

By default, eclipse.ini looks something like this (the exact contents will vary based on operating system and which Eclipse package you have):

-startup ../../../plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar --launcher.library ../../../plugins/org.eclipse.equinox.launcher.cocoa.macosx.x86_64_1.1.100.v20110502 -product org.eclipse.epp.package.jee.product --launcher.defaultAction openFile -showsplash org.eclipse.platform --launcher.XXMaxPermSize 256m --launcher.defaultAction openFile -vmargs -Dosgi.requiredJavaVersion=1.5 -XX:MaxPermSize=256m -Xms40m -Xmx512m

Among other things, this sets the heap space to 40MB initially and a maximum of 512MB, and also specifies a maximum PermGen size of 256MB. A max heap of 512MB might be OK for some users, but it’s often necessary to bump that value up for large project sets or when some third-party plugins are installed.

Specifying the JVM

One of the most recommended options to use is to specify a specific JVM for Eclipse to run on. Doing this ensures that you are absolutely certain which JVM Eclipse will run in and insulates you from system changes that can alter the «default» JVM for your system. Many a user has been tripped up because they thought they knew what JVM would be used by default, but they thought wrong. eclipse.ini lets you be CERTAIN.

The following examples of eclipse.ini demonstrate correct usage of the -vm option.

Note the format of the -vm option — it is important to be exact:

TODO: I know this next statement is not completely true, I just don’t know the exact answer. A path ending in «bin», pointing to the «bin» directory of the Java distro works, and Ed Merks tells me that pointing to a «shared library» works also.

• The value must be the full absolute or relative path to the Java executable, not just to the Java home directory.
• The -vm option must occur after the other Eclipse-specific options (such as -product , —launcher.* , etc), but before the -vmargs option, since everything after -vmargs is passed directly to the JVM.
• For the 32-bit Eclipse executable (eclipse.exe on Windows) a 32-bit JVM must be used and for the 64-bit Eclipse executable a 64-bit JVM must be used. 32-bit Eclipse will not work with a 64-bit JVM.

Here is an example of what eclipse.ini might look like on a Windows system after you’ve added the -vm argument and increased the maximum heap space:

-startup plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar --launcher.library plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.100.v20110502 -product org.eclipse.epp.package.java.product --launcher.defaultAction openFile --launcher.XXMaxPermSize 256M -showsplash org.eclipse.platform --launcher.XXMaxPermSize 256m --launcher.defaultAction openFile -vm C:\Java\JDK\1.8\bin\javaw.exe -vmargs -Dosgi.requiredJavaVersion=1.5 -Xms40m -Xmx1024m

Remember that the exact values will differ slightly depending on operating system and Eclipse package.

-vm value: Windows Example

This is how the -vm argument might look on Windows (your exact path to javaw.exe could be different, of course. Please beware of paths that contain a space, the examples below do not have any spaces, and using quotation marks around paths that contain spaces does not seem to work):

-vm C:\progra~1\Java\jre1.8.0_112\bin\javaw.exe

An alternative way is to insert the following VM option before the -vmargs option in the Eclipse shortcut’s properties (edit the field Target inside the «Shortcut» tab):

-vm C:\jdk1.7.0_21\jre\bin\java.exe

This might not work on all systems. If you encounter «Java was started but returned exit code=1» error while starting the eclipse, modify the -vm argument to point to jvm.dll (exact path could be different):

-vm C:\Development\Java\64bit\jdk1.7.0_09\jre\bin\server\jvm.dll

-vm value: Linux Example

This is how the -vm argument might look on Linux (your exact path to java could be different, of course):

-vm value: macOS Example

On a macOS system, you can find eclipse.ini by right-clicking (or Ctrl+click) on the Eclipse executable in Finder, choose Show Package Contents, and then locate eclipse.ini in the Eclipse folder under Contents . The path is often: /Applications/Eclipse.app/Contents/Eclipse/eclipse.ini

For versions of Mac OS X 10.7+ is something like:

-vm /Library/Java/JavaVirtualMachines//Contents/Home/bin

For example, the latest JDK 1.8 (as of July 2015) is /Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/bin

For standard Mac Java installations and so you don’t have to continually update the setting when you install new Java VMs, set the -vm flag to simply /usr/bin :

If you want to use another JDK (that has the macOS directory layout, like the .tar.gz from AdoptOpenJDK) you should use:

For JDKs without macOS directory layout see: Using a JDK without macOS directory layout

NOTE: Occasionally, depending on the version of your macOS and whether or not you had already run this particular Eclipse installation before, upon launch after changing the -vm, you may run into an error that says «the application is damaged and can’t be opened». This is the expected behavior since you just modified a signed/notarized app. This problem can be overcome by opening the Eclipse application once before changing the eclipse.ini file. Alternatively, running of the following command can fix the issue too: xattr -cr Eclipse.app

Here is additional information:

Perhaps the best way to determine the location for the JDK you want to use is with the utility

/usr/libexec/java_home --verbose

From the list produced by that command, select the JDK you want to use and put that path into the eclipse.ini file, making sure to append /bin/java to the path (eg, /Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/bin/java

Note that the full path can either include java or not. For example, the following will both work:

-vm /Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/bin

-vm /Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/bin/java

Using a JDK without macOS directory layout

If you want to use a JDK that doesn’t follow the macOS directory layout, like the ones installed through SDKMAN!, then you need to specify the path to the libjli.dylib file.

For JDK 11+: /lib/jli/libjli.dylib

For JDK 8: /jre/lib/jli/libjli.dylib

Examples using SDKMAN!

-vm /Users//.sdkman/candidates/java/11.0.8.hs-adpt/lib/jli/libjli.dylib

-vm /Users//.sdkman/candidates/java/8.0.265.hs-adpt/jre/lib/jli/libjli.dylib

NOTE: Beware that if you use current instead of using a specific JDK version identifier it will use the default if you launch the Eclipse.app using the UI (double-click or using Spotlight). If you launch it from a terminal it will use the one currently selected.

See Also

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How to run Eclipse under different version of JDK or JRE

In this article, I will guide you how to change JDK/JRE that runs Eclipse IDE, on Windows operating system. First, you need to know exactly which version of Java on which Eclipse is running.

1. Find the JDK / JRE that runs Eclipse

In Eclipse, click menu Help > About Eclipse IDE. Then in the About Eclipse IDE dialog, click the Installation Details button. Then in the next screen, click Configuration tab. Wait for a moment while Eclipse is retrieving configuration information, and you will see a screen as below:

Find the line that starts with –vm and the value in the next line shows the exact path of JDK/JRE on which Eclipse is running. In the above screenshot, you see Eclipse is running on OpenJDK 11.0.2.

2. How to Change JDK / JRE for Eclipse

You know, Eclipse IDE is written in Java so it needs a JDK/JRE installed to run. By default, the first instance of JDK/JRE found in the PATH environment variable is used to run Eclipse. Consider a typical value of the PATH environment variable like this:

path1;path2;path3;…;%JAVA_HOME%\bin;

In this case, the Java Virtual Machine found in the JAVA_HOME path will run Eclipse IDE. So changing the Java version that run Eclipse is just a matter of updating the value of the JAVA_HOME variable.

However, sometimes it doesn’t work like that. You changed JAVA_HOME points to a newer JDK/JRE, but Eclipse still runs under the old one. Why? What happens?

• An installation of Oracle Java putting its path before your JAVA_HOME, or
• Your Eclipse IDE is configured to stick with a JDK/JRE in its configuration file.

Edit the PATH environment variable on Windows, and you may see a screen as below:

Here, an installation of Oracle Java puts the following line before your JAVA_HOME :

C:\Program Files (x86)\Common Files\Oracle\Java\javapath

That means the JDK/JRE found in this path is always used to run Eclipse. Your JAVA_HOME is ignored. So to change, just move your JAVA_HOME before Oracle’s javapath using the Move Up and Move Down buttons; or delete that Oracle’s javapath. Then restart Eclipse and check configuration again to make sure Eclipse is actually running on the JDK/JRE you specified.

If that doesn’t work, it’s very likely that your Eclipse is somehow configured to stick with a specific version of Java Virtual Machine in its configuration file.

Open the eclipse.ini file in Eclipse’s installation directory in a text editor like Notepad. You may see something like this:

Now, you can change the path after the –vm line to point to a different path of JDK, or delete these two lines to use the Java version specified in the PATH system environment variable.

Phew! That’s how to change the version of Java virtual machine that powers your Eclipse IDE. I hope you found this article helpful.

You can also watch the video version below:

Other Eclipse Tutorials:

About the Author:

Nam Ha Minh is certified Java programmer (SCJP and SCWCD). He started programming with Java in the time of Java 1.4 and has been falling in love with Java since then. Make friend with him on Facebook and watch his Java videos you YouTube.

Источник

Eclipse : How to set java path of JDK/JRE?

To set path of JDK for your project in eclipse follow below steps:

• Right click on your project -> select properties.
• Click in Library tab
• To remove or update JRE/JDK remove existing from list as below.

• Click on add Library and select option as “JRE System Library” and click on Next button.

• If you need to use existing JRE/JDK you can select from installed JRE or if need to add new one click on Add button.
• You will get popup of JRE definition. click on Directory option and select JAVA (JRE/JDK) version home directory as in below screen shot
• Click on Finish button.

• Select one Installed JRE which want to use on your project.
• Click on “Apply and Close” button.

• Finally selected JRE/JDK added to your project.
• Click on “Apply and Close” button.

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