Did you know from java 1.7 you can catch multiple exceptions in a single catch block ?
Until java 1.6 if we wanted to catch multiple exceptions in
a single java program we have to write multiple catch blocks.
For Example in
Java 1.6 environment
class ExceptionTest
{
public
static void main(String[] args)
{
try
{
int
num1=Integer.parseInt(args[0]);
int
num2=Integer.parseInt(args[1]);
int
result=num1/num2;
}
catch
(ArithmeticException e)
{
System.out.println(e.getMessage());
}
catch
(ArrayIndexOutOfBoundsException e)
{
System.out.println(e.getMessage());
}
catch
(NumberFormatException e)
{
System.out.println(e.getMessage());
}
}
}
This leads to duplicity of code making program lengthy and
quite tough to read.
But from java 1.7 we can catch multiple exceptions in a single
catch block. Above example code can be rewritten in Java 1.7 and higher
version as.
class ExceptionTest
{
public
static void main(String[] args)
{
try
{
int
num1=Integer.parseInt(args[0]);
int
num2=Integer.parseInt(args[1]);
int result=num1/num2;
}
catch
(ArithmeticException |NumberFormatException |ArrayIndexOutOfBoundsException e)
{
System.out.println(e.getMessage());
}
}
}
Rules to catch
multiple exceptions
- Exception type parameters must be separated by a pipe symbol.
- We are not allowed to pass alternate exception in a multi exception catch block. Violation it will lead to a compile time error.
- By default variable in multi exception catch block is implicitly final, hence no other assignment on the same variable are allowed. Violation the rule will give a compile time error.
NOTE
·
Byte code generated for above example using java
1.6 and java 1.7 + version have no changes.
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