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Neelakandan R
Neelakandan R

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Exception Handling,throw,throws

try block: Exception Possible Area
catch Block: Exception Handling Area
finally Block: Code Cleansing Area

1) try block inside another try - Nested try

 try { int no1 = 10, no2 = 5; System.out.println(no1/no2); try { int[] ar = new int[no1]; } catch(NegativeArraySizeException na) { } } catch(ArithmeticException ae) { }
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2) try block inside catch block. 

int no1 = 10, no2 = 0; try { System.out.println(no1/no2); } catch(ArithmeticException ae) { Scanner sc = new Scanner(System.in); no2 = sc.nextInt(); try { System.out.println(no1/no2); } catch(ArithmeticException aa) { } }
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3) try catch block inside finally block
Yes, it is possible.

throws:
We can add throws after method signature. We can add any number of throws after method signature. If throws is given, try catch can / should be added at Method calling statement.

public class RecursionDemo { public static void main(String[] args) { RecursionDemo rd = new RecursionDemo(); rd.divide(100, 20); } public void divide(int no1, int no2) throws ArithmeticException, ArrayIndexOutOfBoundsException, NegativeArraySizeException { System.out.println(no1/no2); int[] ar = new int[no2]; for(int i=0; i<10; i++) System.out.println(ar[i]); } }
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public class Patterns { public static void main(String[] args) { RecursionDemo rd = new RecursionDemo(); try { rd.divide(0, 0); } catch(ArithmeticException ae) { System.out.println("Check no2"); } } }
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throw:
Predefined Exceptions.
User Defined Exceptions.
throw is mainly used for User Defined Exceptions. We can add throw inside method definition. After 'throw' keyword,we should mention Exception object.

package pratice; public class Exeception_throw extends RuntimeException { public void checkPassword(String pwd) { if (pwd.length() < 8) { Exeception_throw pe = new Exeception_throw(); throw pe; // throw may used for user define object//throw object } } }
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package pratice; import java.util.Scanner; public class public_login { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter Password: "); String password = sc.next(); Exeception_throw pp = new Exeception_throw(); pp.checkPassword(password); } }
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Enter Password:
123456
Exception in thread "main" pratice.Exeception_throw
at Second/pratice.Exeception_throw.checkPassword(Exeception_throw.java:6)
at Second/pratice.public_login.main(public_login.java:12)

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