[ACCEPTED]-How can I find all the methods that call a given method in Java?-java

For analyzing bytecode, I would recommend 17 ASM. Given a list of Classes to analyze, a 16 visitor can be made which finds the method 15 calls you're interested in. One implementation 14 which analyses classes in a jar file is 13 below.

Note that ASM uses internalNames with '/' instead 12 of '.' as a separator. Specify the target 11 method as a standard declaration without modifiers.

For example, to 10 list methods that could be calling System.out.println("foo") in 9 the java runtime jar:

java -cp "classes;asm-3.1.jar;asm-commons-3.1.jar" App \
    c:/java/jdk/jre/lib/rt.jar \
    java/io/PrintStream  "void println(String)"

Edit: source and line numbers 8 added: Note that this only indicates the 7 last target method invocation per calling 6 method - the original q only wanted to know 5 which methods. I leave it as an exercise for 4 the reader to show line numbers of the calling 3 method declaration, or the line numbers 2 of every target invocation, depending on 1 what you're actually after. :)

results in:

LogSupport.java:44 com/sun/activation/registries/LogSupport log (Ljava/lang/String;)V
LogSupport.java:50 com/sun/activation/registries/LogSupport log (Ljava/lang/String;Ljava/lang/Throwable;)V
...
Throwable.java:498 java/lang/Throwable printStackTraceAsCause (Ljava/io/PrintStream;[Ljava/lang/StackTraceElement;)V
--
885 methods invoke java/io/PrintStream println (Ljava/lang/String;)V

source:

public class App {
    private String targetClass;
    private Method targetMethod;

    private AppClassVisitor cv;

    private ArrayList<Callee> callees = new ArrayList<Callee>();

    private static class Callee {
        String className;
        String methodName;
        String methodDesc;
        String source;
        int line;

        public Callee(String cName, String mName, String mDesc, String src, int ln) {
            className = cName; methodName = mName; methodDesc = mDesc; source = src; line = ln;
        }
    }

    private class AppMethodVisitor extends MethodAdapter {

        boolean callsTarget;
        int line;

        public AppMethodVisitor() { super(new EmptyVisitor()); }

        public void visitMethodInsn(int opcode, String owner, String name, String desc) {
            if (owner.equals(targetClass)
                    && name.equals(targetMethod.getName())
                    && desc.equals(targetMethod.getDescriptor())) {
                callsTarget = true;
            }
        }

        public void visitCode() {
            callsTarget = false;
        }

        public void visitLineNumber(int line, Label start) {
            this.line = line;
        }

        public void visitEnd() {
            if (callsTarget)
                callees.add(new Callee(cv.className, cv.methodName, cv.methodDesc, 
                        cv.source, line));
        }
    }

    private class AppClassVisitor extends ClassAdapter {

        private AppMethodVisitor mv = new AppMethodVisitor();

        public String source;
        public String className;
        public String methodName;
        public String methodDesc;

        public AppClassVisitor() { super(new EmptyVisitor()); }

        public void visit(int version, int access, String name,
                          String signature, String superName, String[] interfaces) {
            className = name;
        }

        public void visitSource(String source, String debug) {
            this.source = source;
        }

        public MethodVisitor visitMethod(int access, String name, 
                                         String desc, String signature,
                                         String[] exceptions) {
            methodName = name;
            methodDesc = desc;

            return mv;
        }
    }


    public void findCallingMethodsInJar(String jarPath, String targetClass,
                                        String targetMethodDeclaration) throws Exception {

        this.targetClass = targetClass;
        this.targetMethod = Method.getMethod(targetMethodDeclaration);

        this.cv = new AppClassVisitor();

        JarFile jarFile = new JarFile(jarPath);
        Enumeration<JarEntry> entries = jarFile.entries();

        while (entries.hasMoreElements()) {
            JarEntry entry = entries.nextElement();

            if (entry.getName().endsWith(".class")) {
                InputStream stream = new BufferedInputStream(jarFile.getInputStream(entry), 1024);
                ClassReader reader = new ClassReader(stream);

                reader.accept(cv, 0);

                stream.close();
            }
        }
    }


    public static void main( String[] args ) {
        try {
            App app = new App();

            app.findCallingMethodsInJar(args[0], args[1], args[2]);

            for (Callee c : app.callees) {
                System.out.println(c.source+":"+c.line+" "+c.className+" "+c.methodName+" "+c.methodDesc);
            }

            System.out.println("--\n"+app.callees.size()+" methods invoke "+
                    app.targetClass+" "+
                    app.targetMethod.getName()+" "+app.targetMethod.getDescriptor());
        } catch(Exception x) {
            x.printStackTrace();
        }
    }

}

Edit: the original question was edited to 9 indicate a runtime solution was needed - this 8 answer was given before that edit and only 7 indicates how to do it during development.

If 6 you are using Eclipse you can right click 5 the method and choose "Open call hierarchy" to 4 get this information.

Updated after reading 3 comments: Other IDEs support this as well 2 in a similar fashion (at least Netbeans 1 and IntelliJ do)

Annotate the method with @Deprecated ( or 5 tag it with @deprecated ), turn on deprecation 4 warnings, run your compile and see which 3 warnings get triggered.

The run your compile 2 bit can be done either by invoking an external 1 ant process or by using the Java 6 compiler API.

1. right click on method
2. Go to references and (depending on your requirement)
   choose workspace/project/Hierarchy.

This pops up a panel that shows all references 1 to this functions. Eclipse FTW !

In eclipse, highlight the method name and 1 then Ctrl+Shift+G

There isn't a way to do this (programmatically) via 13 the Java reflection libraries - you can't 12 ask a java.lang.reflect.Method "which methods do you call?"

That 11 leaves two other options I can think of:

1. Static 10 analysis of the source code. I'm sure this 9 is what the Eclipse Java toolset does - you 8 could look at the Eclipse source behind 7 the JDT, and find what it does when you 6 ask Eclipse to "Find References" to 5 a method.

2. Bytecode analysis. You could inspect 4 the bytecode for calls to the method. I'm 3 not sure what libraries or examples are 2 out there to help with this - but I can't 1 imagine that something doesn't exist.

Yes, most modern IDE:s will let you either 9 search for usages of a method or variable. Alternatively, you 8 could use a debugger and set a trace point 7 on the method entry, printing a stack trace 6 or whatever every time the method is invoked. Finally, you 5 could use some simple shell util to just 4 grep for the method, such as

find . -name '*.java' -exec grep -H methodName {} ;

The only method 3 that will let you find invokations made 2 through some reflection method, though, would 1 be using the debugger.

I made a small example using @Chadwick's 3 one. It's a test that assesses if calls 2 to getDatabaseEngine() are made by methods 1 that implement @Transaction.

/**
 * Ensures that methods that call {@link DatabaseProvider#getDatabaseEngine()}
 * implement the {@link @Transaction} annotation.
 *
 * @throws Exception If something occurs while testing.
 */
@Test
public void ensure() throws Exception {
    final Method method = Method.getMethod(
            DatabaseEngine.class.getCanonicalName() + " getDatabaseEngine()");

    final ArrayList<java.lang.reflect.Method> faultyMethods = Lists.newArrayList();

    for (Path p : getAllClasses()) {
        try (InputStream stream = new BufferedInputStream(Files.newInputStream(p))) {
            ClassReader reader = new ClassReader(stream);


            reader.accept(new ClassAdapter(new EmptyVisitor()) {
                @Override
                public MethodVisitor visitMethod(final int access, final String name, final String desc, final String signature, final String[] exceptions) {

                    return new MethodAdapter(new EmptyVisitor()) {
                        @Override
                        public void visitMethodInsn(int opcode, String owner, String nameCode, String descCode) {
                            try {
                                final Class<?> klass = Class.forName(Type.getObjectType(owner).getClassName());
                                if (DatabaseProvider.class.isAssignableFrom(klass) &&
                                        nameCode.equals(method.getName()) &&
                                        descCode.equals(method.getDescriptor())) {

                                    final java.lang.reflect.Method method = klass.getDeclaredMethod(name,
                                            getParameters(desc).toArray(new Class[]{}));

                                    for (Annotation annotation : method.getDeclaredAnnotations()) {
                                        if (annotation.annotationType().equals(Transaction.class)) {
                                            return;
                                        }
                                    }

                                    faultyMethods.add(method);

                                }
                            } catch (Exception e) {
                                Throwables.propagate(e);
                            }
                        }
                    };
                }
            }, 0);

        }
    }

    if (!faultyMethods.isEmpty()) {
        fail("\n\nThe following methods must implement @Transaction because they're calling getDatabaseEngine().\n\n" + Joiner.on("\n").join
                (faultyMethods) + "\n\n");
    }

}

/**
 * Gets all the classes from target.
 *
 * @return The list of classes.
 * @throws IOException If something occurs while collecting those classes.
 */
private List<Path> getAllClasses() throws IOException {
    final ImmutableList.Builder<Path> builder = new ImmutableList.Builder<>();
    Files.walkFileTree(Paths.get("target", "classes"), new SimpleFileVisitor<Path>() {
        @Override
        public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException {
            if (file.getFileName().toString().endsWith(".class")) {
                builder.add(file);
            }
            return FileVisitResult.CONTINUE;
        }
    });

    return builder.build();
}

/**
 * Gets the list of parameters given the description.
 *
 * @param desc The method description.
 * @return The list of parameters.
 * @throws Exception If something occurs getting the parameters.
 */
private List<Class<?>> getParameters(String desc) throws Exception {
    ImmutableList.Builder<Class<?>> obj = new ImmutableList.Builder<>();

    for (Type type : Type.getArgumentTypes(desc)) {
        obj.add(ClassUtils.getClass(type.getClassName()));
    }

    return obj.build();
}

1)In eclipse it is ->right click on the 3 method and select open call hierarchy or 2 CLT+ALT+H

2)In jdeveloper it is -> right click on 1 the method and select calls or ALT+SHIFT+H

The closest that I could find was the method 2 described in this StackOverflow questions 1 selected answer.check this out