Difference between revisions of "JAVA: try, catch, throw & throws di Java"
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− | What is an Exception? | + | ==What is an Exception?== |
An exception is an “unwanted or unexpected event”, which occurs during the execution of the program i.e, at run-time, that disrupts the normal flow of the program’s instructions. When an exception occurs, execution of the program gets terminated. | An exception is an “unwanted or unexpected event”, which occurs during the execution of the program i.e, at run-time, that disrupts the normal flow of the program’s instructions. When an exception occurs, execution of the program gets terminated. | ||
− | Why does an Exception occur? | + | ==Why does an Exception occur?== |
An exception can occur due to several reasons like Network connection problem, Bad input provided by user, Opening a non-existing file in your program etc | An exception can occur due to several reasons like Network connection problem, Bad input provided by user, Opening a non-existing file in your program etc | ||
− | Blocks & Keywords used for exception handling | + | ==Blocks & Keywords used for exception handling== |
− | 1.try: The try block contains set of statements where an exception can occur. | + | ===1.try:=== |
+ | The try block contains set of statements where an exception can occur. | ||
try | try | ||
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} | } | ||
− | 2.catch : Catch block is used to handle the uncertain condition of try block. A try block is always followed by a catch block, which handles the exception that occurs in associated try block. | + | ===2.catch:=== |
+ | Catch block is used to handle the uncertain condition of try block. A try block is always followed by a catch block, which handles the exception that occurs in associated try block. | ||
catch | catch | ||
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3.throw: Throw keyword is used to transfer control from try block to catch block. | 3.throw: Throw keyword is used to transfer control from try block to catch block. | ||
− | 4.throws: Throws keyword is used for exception handling without try & catch block. It specifies the exceptions that a method can throw to the caller and does not handle itself. | + | ===4.throws:=== |
+ | Throws keyword is used for exception handling without try & catch block. It specifies the exceptions that a method can throw to the caller and does not handle itself. | ||
− | 5.finally: It is executed after catch block. We basically use it to put some common code when there are multiple catch blocks. | + | ===5.finally:=== |
+ | It is executed after catch block. We basically use it to put some common code when there are multiple catch blocks. | ||
Example of an Exception generated by system is given below : | Example of an Exception generated by system is given below : | ||
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I am in final block | I am in final block | ||
− | + | Contoh throw keyword: | |
− | |||
// Java program to demonstrate working of throws | // Java program to demonstrate working of throws |
Revision as of 09:08, 11 May 2022
What is an Exception?
An exception is an “unwanted or unexpected event”, which occurs during the execution of the program i.e, at run-time, that disrupts the normal flow of the program’s instructions. When an exception occurs, execution of the program gets terminated.
Why does an Exception occur?
An exception can occur due to several reasons like Network connection problem, Bad input provided by user, Opening a non-existing file in your program etc
Blocks & Keywords used for exception handling
1.try:
The try block contains set of statements where an exception can occur.
try { // statement(s) that might cause exception }
2.catch:
Catch block is used to handle the uncertain condition of try block. A try block is always followed by a catch block, which handles the exception that occurs in associated try block.
catch { // statement(s) that handle an exception // examples, closing a connection, closing // file, exiting the process after writing // details to a log file. }
3.throw: Throw keyword is used to transfer control from try block to catch block.
4.throws:
Throws keyword is used for exception handling without try & catch block. It specifies the exceptions that a method can throw to the caller and does not handle itself.
5.finally:
It is executed after catch block. We basically use it to put some common code when there are multiple catch blocks.
Example of an Exception generated by system is given below :
Exception in thread "main" java.lang.ArithmeticException: divide by zero at ExceptionDemo.main(ExceptionDemo.java:5) ExceptionDemo: The class name main:The method name ExceptionDemo.java:The file name java:5:line number // Java program to demonstrate working of try, // catch and finally class Division { public static void main(String[] args) { int a = 10, b = 5, c = 5, result; try { result = a / (b - c); System.out.println("result" + result); } catch (ArithmeticException e) { System.out.println("Exception caught:Division by zero"); } finally { System.out.println("I am in final block"); } } }
Output:
Exception caught:Division by zero I am in final block
Contoh throw keyword:
// Java program to demonstrate working of throws class ThrowsExecp { // This method throws an exception // to be handled // by caller or caller // of caller and so on. static void fun() throws IllegalAccessException { System.out.println("Inside fun(). "); throw new IllegalAccessException("demo"); } // This is a caller function public static void main(String args[]) { try { fun(); } catch (IllegalAccessException e) { System.out.println("caught in main."); } } }
Output:
Inside fun(). caught in main.