NetBeans 8.2 does not open on Mac OS

Question

I am trying to start NetBeans 8.2 on a Macbook Pro and it's not working.

It shows the splash screen, then after a while it shuts down without starting anything.

Running from the command-line I can see this error:

Oct 02, 2017 7:40:28 PM org.netbeans.ProxyURLStreamHandlerFactory register
SEVERE: No way to find original stream handler for jar protocol
java.lang.reflect.InaccessibleObjectException: Unable to make field transient java.net.URLStreamHandler java.net.URL.handler accessible: module java.base does not "opens java.net" to unnamed module @7823a2f9
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:337)
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:281)
    at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:175)
    at java.base/java.lang.reflect.Field.setAccessible(Field.java:169)
    at org.netbeans.ProxyURLStreamHandlerFactory.register(ProxyURLStreamHandlerFactory.java:82)
    at org.netbeans.JarClassLoader.<clinit>(JarClassLoader.java:141)
    at org.netbeans.MainImpl.execute(MainImpl.java:178)
    at org.netbeans.MainImpl.main(MainImpl.java:85)
    at org.netbeans.Main.main(Main.java:83)

Looks like Java 9 got bundled with it and it's causing an error. The documentation implies that NetBeans 8.2 uses JDK 8!?

How to use my own java to run NetBeans, or how to get NetBeans to start without this error?

Answer 1

Yes, NetBeans 8.2 does use JDK 1.8, and specifically does not support JDK 1.9.

It's unclear from the OP which version of Java is desired to run with NetBeans, but the version of NetBeans to use is governed by the version of Java to be used:

[1] For Java 8, use Netbeans 8.2. Note that Java 9 is not supported. You can download NetBeans 8.2 bundled with JDK 8u141 for Mac OS here:

http://www.oracle.com/technetwork/articles/javase/jdk-netbeans-jsp-142931.html

Once it has been installed it no specific configuration for Java should be necessary.

[2] For Java 9 you must use a Development Build of NetBeans. That can be downloaded from http://bits.netbeans.org/download/trunk/nightly/latest/ but be sure that Mac OS X is selected from the Platform drop list before clicking Download.

For any version of NetBeans you can specify your own version of Java as follows:

• Start NetBeans and select Java Platforms from the Tools menu.

• Click the Add Platform... button.

• Complete the wizard to locate the version of Java you want to use.

One final point: there is no problem having multiple versions of NetBeans installed and running concurrently using different JDKs, typically NetBeans 8.2 with JDK 1.8 and NetBeans Dev Build with JDK 1.9.

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Update:

If NetBeans closes itself down on startup it may have an invalid JDK path. To change the JDK that NetBeans uses:

• Locate the file netbeans.conf. It should be in the etc directory under the NetBeans installation directory.

• Edit that file in a text editor. Locate the line containing the property netbeans_jdkhome. On my Windows 10 installation it looks like this:

  netbeans_jdkhome="C:\Java\jdk1.8.0_121"

• Change the value for that property to specify the path to the desired JDK, save the file and restart NetBeans.

Answer 2

As pointed in the comments:

I had tried to set netbeans_jdkhome in /Applications/NetBeans/NetBeans\ 8.2.app/Contents/Resources/NetBeans/etc/netbeans.conf to point to JDK 10, but still it did not work.

I had to install JDK 8, and set netbeans_jdkhome="/Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk/Contents/Home"

Uninstalling JDK 10 and using JDK 8 worked for me and setting netbeans_jdkhome="/Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk/Contents/Home" worked quite well.