How to check if a java class has a particular method in it?

Use reflection.

import java.lang.reflect.Method;

boolean hasMethod = false;
Method[] methods = foo.getClass().getMethods();
for (Method m : methods) {
  if (m.getName().equals(someString)) {
    hasMethod = true;
    break;
  }
}

Edit:

So you want to invoke the method if it exists. This is how you do it:

if (m.getName().equals(someString)) {
  try {
    Object result = m.invoke(instance, argumentsArray);
    // Do whatever you want with the result.
  } catch (Exception ex) { // For simplicity's sake, I am using Exception.
                           // You should be handling all the possible exceptions
                           // separately.
    // Handle exception.
  }
}

One method is mentioned by @missingfaktor and another is below (if you know the name and parameters of the api).

Say you have one method which takes no args:

Method methodToFind = null;
try {
  methodToFind = YouClassName.class.getMethod("myMethodToFind", (Class<?>[]) null);
} catch (NoSuchMethodException | SecurityException e) {
  // Your exception handling goes here
}

Invoke it if present:

if(methodToFind == null) {
   // Method not found.
} else {
   // Method found. You can invoke the method like
   methodToFind.invoke(<object_on_which_to_call_the_method>, (Object[]) null);
}

Say you have one method which takes native int args:

Method methodToFind = null;
methodToFind = YouClassName.class.getMethod("myMethodToFind", new Class[] { int.class });

Invoke it if present:

if(methodToFind == null) {
   // Method not found.
} else {
   // Method found. You can invoke the method like
   methodToFind.invoke(<object_on_which_to_call_the_method>, invoke(this,
      Integer.valueOf(10)));
}

Say you have one method which takes boxed Integer args:

Method methodToFind = null;
methodToFind = YouClassName.class.getMethod("myMethodToFind", new Class[] { Integer.class });

Invoke it if present:

if(methodToFind == null) {
   // Method not found.
} else {
   // Method found. You can invoke the method like
   methodToFind.invoke(<object_on_which_to_call_the_method>, invoke(this,
      Integer.valueOf(10)));
}

Using the above soln to invoke method won't give you compilation errors. Updated as per @Foumpie