Java: Add initial version of empty method query

java/ql/test/query-tests/EmptyMethod/EmptyMethod.expected

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+| Test.java:16:17:16:18 | f2 | Empty method found. |

java/ql/test/query-tests/EmptyMethod/EmptyMethod.qlref

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+Language Abuse/EmptyMethod.ql

java/ql/test/query-tests/EmptyMethod/Test.java

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+import org.aspectj.lang.annotation.Pointcut;
+
+public class Test {
+
+    // COMPLIANT
+    public void f() {
+        int i = 0;
+    }
+
+    // COMPLIANT
+    public void f1() {
+        // intentionally empty
+    }
+
+    // NON_COMPLIANT
+    public void f2() {}
+
+    // COMPLIANT - exception
+    @Pointcut()
+    public void f4() {}
+
+    public abstract class TestInner {
+
+        public abstract void f(); // COMPLIANT - intentionally empty
+    }
+
+}
+
+

java/ql/test/query-tests/EmptyMethod/options

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+//semmle-extractor-options: --javac-args -cp ${testdir}/../../stubs/aspectj