[fixes #3748] Patch SourceTypeConverter to avoid parsing empty strings

test/eclipse/resource/noerrors/synchronizedUsage/Usage.java

@@ -0,0 +1,10 @@
+package pkg;
+
+public class Usage {
+	private ClassWithSynchronized test;
+	
+	// Prevent "The value of the field Usage.test is not used"
+	public void test() {
+		test.test();
+	}
+}