public static Method findMethodExactIfExists(String className, ClassLoader classLoader, String methodName, Object... parameterTypes) {
        try {
            return findMethodExact(className, classLoader, methodName, parameterTypes);
        } catch (NoSuchMethodError e) {
            return null;
        } catch (ClassNotFoundError e) {
            return null;
        }
    }
Look up and return a method if it exists.
Like {@link #findMethodExact(String, ClassLoader, String, Object...)}, but doesn't throw an
exception if the method doesn't exist.

@param className      The name of the class which implements the method.
@param classLoader    The class loader for resolving the target and parameter classes.
@param methodName     The target method name.
@param parameterTypes The parameter types of the target method.
@return A reference to the method, or {@code null} if it doesn't exist.
android/android_framework/base/src/main/java/util/XposedHelpers.java