Problems in converting ArrayList to a Strin gArray

[JT Reddy]

Dear All,

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//pNames is an ArrayList & contains 2 String objects

String[] pNames_strArray = (String[]) pNames.toArray(); //not working
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I want to convert ArrayList to a string array, but I am getting ClassCastException. What is the right way to do it. TIA

[Ernest Friedman-Hill]

The version of toArray() that takes no arguments will always return an Object[]. If you want (for example) a String[], then you need to pass a String[] in as an argument. It can be any length, but if you're allocating one anyway, make it the right size and then toArray will use the one you pass in. So...

String[] pNames_strArray = (String[]) pNames.toArray(new String[pNames.size()]);

This is so common that many IDEs let you type this whole line with one keystroke.

[Garrett Rowe]

Originally posted by Ernest Friedman-Hill:
The version of toArray() that takes no arguments will always return an Object[]. If you want (for example) a String[], then you need to pass a String[] in as an argument. It can be any length, but if you're allocating one anyway, make it the right size and then toArray will use the one you pass in. So...

String[] pNames_strArray = (String[]) pNames.toArray(new String[pNames.size()]);

This is so common that many IDEs let you type this whole line with one keystroke.

Actually if you do it the way Ernest suggests, you don't need the cast at all:

String[] pNames_strArray = (String[]) pNames.toArray(new String[pNames.size()]);

becomes:

String[] pNames_strArray = pNames.toArray(new String[pNames.size()]);

[Ernest Friedman-Hill]

In Tiger, that is. In JDK 1.4 and earlier, you still need the cast.
[ February 03, 2006: Message edited by: Ernest Friedman-Hill ]

[JT Reddy]

Thanks a lot for the input.