Bug 77320 Junit performance [JUnit]
We have 2315 unit tests. When run from Eclipse, it's reporting to take ~122 seconds. When run from ant, it reports taking ~25 seconds. The majority of this time is spent with the JUnit view showing "Launching...". This has gotten worse and worse as we add more UTs. I expect Eclipse to be slower than Ant, but not by this much.
org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/ui/TestRunnerViewPart.java
public void elementChanged(ElementChangedEvent event) {
			processDelta(event.getDelta());				
		}
		
		private boolean processDelta(IJavaElementDelta delta) {
			int kind= delta.getKind();
			int details= delta.getFlags();
			int type= delta.getElement().getElementType();
			
			switch (type) {
				
				case IJavaElement.JAVA_MODEL:
				case IJavaElement.JAVA_PROJECT:
				case IJavaElement.PACKAGE_FRAGMENT_ROOT:
				case IJavaElement.PACKAGE_FRAGMENT:
					
					if (kind != IJavaElementDelta.CHANGED || details != IJavaElementDelta.F_CHILDREN) {
						codeHasChanged();
						return false;
					}
					break;
				case IJavaElement.COMPILATION_UNIT:
					
					
					if ((details & IJavaElementDelta.F_PRIMARY_WORKING_COPY) != 0) 
						return true;
					codeHasChanged();
					return false;