[fixes #3706] Add null check for compilation unit

test/eclipse/resource/noerrors/builderJavadoc/BuilderJavadoc.java

@@ -0,0 +1,14 @@
+package pkg;
+
+import lombok.Builder;
+
+@Builder
+public class BuilderJavadoc {
+	/**
+	 * Javadoc
+	 * 
+	 * @param test ABC
+	 * @return test
+	 */
+	private String test;
+}

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

@@ -0,0 +1,7 @@
+package pkg;
+
+public class Usage {
+	public void test() {
+		BuilderJavadoc.builder().test("test").build();
+	}
+}