EffectivePomMojo encoding fallback can return null

In src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java:110:

String encoding = output != null ? project.getModel().getModelEncoding() : System.getProperty("file.encoding");

System.getProperty("file.encoding") can theoretically return null.

Open src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java at line 110 and inspect how the encoding is selected when output is null. Run the relevant Maven plugin tests, or the project test suite if no narrower test is identified. Done means the fallback remains valid even when the system file.encoding property is unavailable.

Written by the indexing model from the issue text.