Compact Maven parallel flag -T<N> in Goals not recognized as parallel build

[xerno]

Apache NetBeans version

Apache NetBeans 29

What happened

Maven accepts both -T 2 (two tokens) and -T2 (single token) as equivalent parallel build syntax. In the NetBeans Goals field, these naturally produce different nbactions.xml structures:

• -T 2 -> <goal>-T</goal><goal>2</goal> - works correctly, parallel build detected, output displays fine
• -T2 -> <goal>-T2</goal> - build runs fine, but Output window throws NPE:

  java.lang.NullPointerException: Cannot read field "type" because "start" is null
      at o.n.m.maven.execute.CommandLineOutputHandler.trimTree(CommandLineOutputHandler.java:588)                                  
      at o.n.m.maven.execute.CommandLineOutputHandler.processExecEvent(CommandLineOutputHandler.java:475)                          
      at o.n.m.maven.execute.CommandLineOutputHandler$Output.run(CommandLineOutputHandler.java:293)  

It appears that the compact form is not recognized as a parallel build, so the output tree-folding stays active and crashes on interleaved events from concurrent modules.

Workaround: Use -T 2 (with space) instead of -T2 in the Goals field.

Language / Project Type / NetBeans Component

Java Maven multi-module project

How to reproduce

1. Open any Maven multi-module project with at least 2 independent modules
2. In the Goals field (or directly in nbactions.xml), configure a build action with -T2 as a single goal:

  <goals>                                                                                                                          
      <goal>-T2</goal>                                                                                                             
      <goal>clean</goal>                                                                                                           
      <goal>install</goal>                                        
  </goals>         

3. Run the action
4. Observe the Output window — build succeeds but the output tree is corrupted and the NPE appears

For comparison, change to -T 2 (two separate goals):

  <goals>                                                                                                                          
      <goal>-T</goal>                                                                                                              
      <goal>2</goal>                                                                                                               
      <goal>clean</goal>                                          
      <goal>install</goal>
  </goals>     

This works correctly.

Did this work correctly in an earlier version?

No / Don't know

Operating System

Mac OS X version 26.5 / aarch64

JDK

OpenJDK 64-Bit Server VM 25.0.2+10-LTS

Apache NetBeans packaging

Apache NetBeans binary zip

Anything else

Related:

• Broken output when using mvnd in multimodule project #5479
• Maven threaded build output #3675

Are you willing to submit a pull request?

Yes