Why catch (NullPointerException e)?

[igor]

Hi!

I noticed that 
try { System.getSecurityManager().checkXXX(); }
catch(NullPointerException e) { }

code is used throw classpath. What is a reason for that? 

I wrote a simple test case like:
class x 
{
/*
 x() throws SecurityException {
  try {
   System.getSecurityManager().checkCreateClassLoader();
  } catch(NullPointerException e) {
 }
*/
 x() throws SecurityException {
  SecurityManager sm = System.getSecurityManager();
  if (sm != null) { sm.checkCreateClassLoader(); }
 }
}

And here what I got for code size after 
javac -O -g:none x.java:

x.class with NullPointerException check: 377 bytes
x.class with if check:                   335 bytes

As regarding speed I really doubed that one can gain
anything: with Jit and brunch prediction I would expect
that even when SecurityManager is installed, the "if" case would run as fast as catch 
one, and without SecurityManager (which a common case for many Java applications), it 
would run I guess at least 10 times faster.

Besides, this "optimization" can hide potential NullPointerException bugs in 
SecurityManager implementation.

Regards, Igor

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