[NETBEANS-4049] UnsupportedClassVersionError when running JDK14 code with --enable-preview

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 11.3
• Component/s: platform - Execution, platform - Options&Settings
• Labels: jdk14

Environment

Product Version: Apache NetBeans IDE 11.3
Java: 14; OpenJDK 64-Bit Server VM 14+36-1461
Runtime: OpenJDK Runtime Environment 14+36-1461
System: Windows 10 version 10.0 running on amd64; Cp1252; en_US (nb)
User directory: C:\Users\johndoe\AppData\Roaming\NetBeans\11.3
Cache directory: C:\Users\johndoe\AppData\Local\NetBeans\Cache\11.3

• Assignee: Unassigned
• Reporter: Rick Hegarty
• Created: 21/Mar/20 18:45
• Updated: 21/Mar/20 18:45

Description

I have installed NB 11.3 on Windows 10, with JDK 14 as its only Java platform.

I created a simple Java with Ant project, and wrote code using "arrow case" labels in a switch block:

 

static boolean isModifiable(char c) {
    boolean canModify = switch (c) {
        case 'ñ', 'Ñ' ->
            false;
        default ->
            true;
    };
    return canModify;
 }

 

NetBeans detected that this was a JEP 354 preview feature, and set --enable-preview for compilation (Properties > Build > Compiling > Additional Compiler Options) and execution (Properties > Run > VM Options).

The code compiled with no problems, but running it (Run > Run Project) resulted in this error:

 

run:
Error: LinkageError occurred while loading main class com.Diacritics java.lang.UnsupportedClassVersionError: com/Diacritics (class file version 57.65535) was compiled with preview features that are unsupported. This version of the Java Runtime only recognizes preview features for class file version 58.65535
C:\Users\johndoe\AppData\Local\NetBeans\Cache\11.3\executor-snippets\run.xml:111: The following error occurred while executing this line:
C:\Users\johndoe\AppData\Local\NetBeans\Cache\11.3\executor-snippets\run.xml:68: Java returned: 1
BUILD FAILED (total time: 0 seconds)

When I build the project the message is logged 

To run this application from the command line without Ant, try:
java -jar "D:\NB113\Diacritics\dist\Diacritics.jar"

If I run from the command line with JDK 14 on the PATH, using what NetBeans proposes (i.e. java jar "D:\NB113\Diacritics\dist\Diacritics.jar") I also get the linkage error described above. However, when I added the -enable-preview option to the command line call it works fine, as shown in this screen shot:

This suggests that when running the project within NetBeans the VM Option --enable-preview is being ignored.

There is no issue when creating a Java application using Java with Maven that contains the same code. This is only an issue for Java with Ant projects.