The java.lang.reflect.Method.getExceptionTypes() method of “Method class” returns an array of Exception Type Class Objects declared to be thrown by the method object to handle exception inside the method. All the exceptions handled by method using thrown clause, are returned as array of Class objects using this method. This method returns an array of length 0 if the method, on which this method is applied, declares no exceptions in its throws clause. Syntax:
public Class<?>[] getExceptionTypes()
Return Value: This method returns an array of the exception class declared using thrown clause by the this Method object Below programs illustrates getExceptionTypes() method of Method class: Example 1: Print all Exceptions
Java
/** Program Demonstrate getExceptionTypes() method* of Method Class.*/import java.lang.reflect.Method;public class GFG { // Main method public static void main(String[] args) { try { // create class object Class classobj = demoClass.class; // get list of method Objects Method[] methods = classobj.getMethods(); // loop through list for (Method method : methods) { // check for method with their name if (method.getName().equals("setValue") || method.getName().equals("getValue")) { // get Exception Types Class[] exceptions = method.getExceptionTypes(); // print exception Types thrown by method Object System.out.println("Exception Thrown by Method: " + method.getName()); System.out.println("Exception Array length: " + exceptions.length); for (Class c : exceptions) { System.out.println(c.getName()); } } } } catch (Exception e) { e.printStackTrace(); } }}// a simple classclass demoClass { // throw some exception by method public void setValue(String value) throws ClassNotFoundException, ArrayIndexOutOfBoundsException, ArithmeticException { } // method throwing no exception public String getValue(String value) { return value; }} |
Exception Thrown by Method: getValue Exception Array length: 0 Exception Thrown by Method: setValue Exception Array length: 3 java.lang.ClassNotFoundException java.lang.ArrayIndexOutOfBoundsException java.lang.ArithmeticException
Example 2: Check whether certain defined Exception is thrown by Method object or not. If yes, then print true, otherwise print false.
Java
// Program Demonstrate getExceptionTypes() method// Using getExceptionTypes() method of Method Classimport java.lang.reflect.Method;// a simple classclass GFGSampleClass { String value; // throw some exception by method public void setValue(String value) throws ClassNotFoundException, ArrayIndexOutOfBoundsException, ArithmeticException { this.value = value; }}public class GFG { // Main method public static void main(String[] args) { try { // create class object Class classobj = GFGSampleClass.class; // get list of method Objects Method[] methods = classobj.getMethods(); // loop through list for (Method method : methods) { // check for method with their name if (method.getName().equals("setValue")) { // check whether method throw // IndexOutOfBoundsException Exception Class exceptionObj = IndexOutOfBoundsException.class; boolean response = isCertainExceptionIsThrown(method, exceptionObj); System.out.println("IndexOutOfBoundsException is " + "thrown by setValue(): " + response); } } } catch (Exception e) { e.printStackTrace(); } } /* * Return true if the given method throws the * exception passed as Parameter. */ private static boolean isCertainExceptionIsThrown(Method method, Class<?> exceptionName) { // get all exception list Class exceptions[] = method.getExceptionTypes(); for (int i = 0; i < exceptions.length; i++) { // check exception thrown or not if (exceptions[i] == exceptionName) { return true; } } return false; }} |
IndexOutOfBoundsException is thrown by setValue(): false
Reference: https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Method.html#getExceptionTypes–
