Name: viR10068 Date: 04/23/2004


The spec says for the method java.lang.Runtime.exec(String):
"...
This is a convenience method. An invocation of the form exec(command)
behaves in exactly the same way as the invocation exec(command, null, null).
...
Throws:
IllegalArgumentException - If command is empty"

The spec says for the method java.lang.Runtime.exec(String, String[], File):
"An invocation of the form exec(command, envp, dir) behaves in exactly the
same way as the invocation exec(cmdarray, envp, dir), where cmdarray is an
array of all the tokens in command.
 More precisely, the command string is broken into tokens using a StringTokenizer
created by the call new StringTokenizer(command) with no further modification of
the character categories. The tokens produced by the tokenizer are then placed in
the new string array cmdarray, in the same order.
...
Throws:
IllegalArgumentException - If command is empty"

The spec says for the method java.lang.Runtime.exec(String[], String[], File):
"...
Throws:
IndexOutOfBoundsException - If cmdarray is an empty array (has length 0)"

So, according to the spec the method java.lang.Runtime.exec("") can
throw 2 different exception for 1 error:
1) the IllegalArgumentException: as described in the Throws clause.
2) the IndexOutOfBoundsException: according to the statement "behaves in exactly
the same way as the invocation exec(command, null, null)".
Note, that the (new StringTokenizer("")).countTokens() return 0 and constructed
array of all the tokens in command is an empty array.

The words "behaves in exactly the same way" in the exec(String, String[], File)
method description contradicts to the Throws clause and may mislead user.
Some clarification is needed. For example:
"behaves in exactly the same way (except the case when command is empty)"

Note that the Sun's RI throws the IndexOutOfBoundsException for jdk up
to 1.4.0 and throws the IllegalArgumentException starting from the jdk1.4.1:
% java -showversion Hello
java version "1.4.1"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1-b21)
Java HotSpot(TM) Client VM (build 1.4.1-b21, mixed mode)

Exception in thread "main" java.lang.IllegalArgumentException: Empty command
        at java.lang.Runtime.exec(Runtime.java:417)
        at java.lang.Runtime.exec(Runtime.java:364)
        at java.lang.Runtime.exec(Runtime.java:326)
        at Hello.main(Hello.java:7)
% java -showversion Hello
java version "1.4.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-b92)
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)

Exception in thread "main" java.lang.IndexOutOfBoundsException
        at java.lang.Runtime.exec(Runtime.java:531)
        at java.lang.Runtime.exec(Runtime.java:416)
        at java.lang.Runtime.exec(Runtime.java:358)
        at java.lang.Runtime.exec(Runtime.java:322)
        at Hello.main(Hello.java:7)
%

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