fix(java11) set compiler java compliance to 1.8

bundles/plugins/org.bonitasoft.studio.common.repository/src-test/java/org/bonitasoft/studio/common/repository/core/ProjectClasspathFactoryTest.java

@@ -77,6 +77,7 @@ public class ProjectClasspathFactoryTest {
         doReturn(executionEnvironment).when(bonitaBPMProjectClasspath).javaRuntimeEnvironment();
         doReturn(javaProject).when(bonitaBPMProjectClasspath).asJavaProject(repository);
         doReturn(newArrayList(aSourceRepositoryStore(), aRepositoryStore())).when(repository).getAllStores();
+        doNothing().when(bonitaBPMProjectClasspath).updateCompilerJavaCompliance(notNull(String.class));
     }
 
     private IRepositoryStore<?> aSourceRepositoryStore() {

bundles/plugins/org.bonitasoft.studio.common.repository/src/org/bonitasoft/studio/common/repository/core/ProjectClasspathFactory.java

@@ -59,7 +59,7 @@ public class ProjectClasspathFactory {
         updateCompilerJavaCompliance(CompilerOptions.VERSION_1_8);
     }
 
-    private void updateCompilerJavaCompliance(String javaVersion) {
+    protected void updateCompilerJavaCompliance(String javaVersion) {
         Hashtable<String, String> options = JavaCore.getOptions();
         options.put(CompilerOptions.OPTION_TargetPlatform, javaVersion);
         options.put(CompilerOptions.OPTION_Source, javaVersion);