NoSuchAlgorithmException

I am trying to make an asymetrical encryption using RSA algorithms in java.
Every time I use the following kind of reference...

KeyPairGenerator keygen = KeyPairGenerator.getInstance("RSA");

...The IDE underlines it in red and says...

"unreported exception java.security.NoSuchAlgorithmException;must be caught or declared to be thrown"

...My questions are...
1) Why am I getting a "NoSuchAlgorithm" exception?
2) What is "catching"? What about "Declaring"? Throwing?
3) if I "caught", "declared" or "threw" this exception, would the program still work as planned?

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Originally Posted by soccermiles

1) Why am I getting a "NoSuchAlgorithm" exception?
2) What is "catching"? What about "Declaring"? Throwing?

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Check out the tutorials on "Exceptions"

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3) if I "caught", "declared" or "threw" this exception, would the program still work as planned?

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Try it, you've got nothing to lose. :)

A lot of other people have programs that work that include that exact same line, along with alot of others using "getInstance("RSA")", I think it's my jre or jdk.

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Originally Posted by soccermiles

A lot of other people have programs that work that include that exact same line, along with alot of others using "getInstance("RSA")", I think it's my jre or jdk.

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You might not want to be so quick to blame something you're not familiar with. Have you looked at the KeyPairGenerator API, in particular the getInstance(String algorithm) method? To be honest, I know nothing about using this class to encrypt (or encryption in general), but the API tells me all I need to know, stating:

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throws NoSuchAlgorithmException

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and this tells me that there's nothing wrong with your jre or jdk.

Again, please have a look at the Exceptions section of the tutorials. It's a very helpful article.

Much luck.

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Originally Posted by soccermiles

A lot of other people have programs that work that include that exact same line, along with alot of others using "getInstance("RSA")", I think it's my jre or jdk.

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It's not. But you do need to learn about Exceptions, and how to catch and throw them, as Fubarable said. You'll need to learn this sooner or later anyway, and now's as good a time as any.

-Gary-

Plenty of other people use this line, without using ANY exception handling code.
I think mebbe I should check the class itself, and find out whether it actually has the Algorithm in it. mebbe its called something else...

NVMNVMNVM!!
I LOOKED AND NOW I KNOW A LITTLE BIT ABOUT EXCEPTION HANDLING AND IT WORKED OMGOMGOMGOMGOMGOMGOMG xD
TYTYTYTYTYTYTY.

Quote:

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Originally Posted by soccermiles

Plenty of other people use this line, without using ANY exception handling code.

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Can you show us a link demonstrating this?

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Originally Posted by soccermiles

Plenty of other people use this line, without using ANY exception handling code.
I think mebbe I should check the class itself, and find out whether it actually has the Algorithm in it. mebbe its called something else...

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From KeyPairGenerator (Java Platform SE 6)

Code:

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public static KeyPairGenerator getInstance(String algorithm)
                                    throws NoSuchAlgorithmException

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The method you are trying to call clearly throws a NoSuchAlgorithmException, so you either need to catch it, or declare that your method throws it too.

-Gary-