Runtime.exec()的问题？

最近写的一个程序要在Linux下用到Runtime.getRuntime().exec(command)，可是发现一个奇怪的问题。先看看代码：

 public static void main(String[] args) {
 　　try {
 　　　　String[] command = {"kill", "-9", "`ps -ef | grep '程序名' | awk '{print $2}'`"};
 　　　　Process p = Runtime.getRuntime().exec(command);
 　　　　p.waitFor();
 　　　　System.out.println("exit code = " + p.exitValue());
 　　} catch (Exception e) {
 　　　　e.printStackTrace();
 　　}
 }

这段代码在Solaris10上面执行的结果是exit code = 1，希望被kill的程序也没kill成功。可是如果我在console里面直接执行：

kill -9 `ps -ef | grep '程序名' | awk '{print $2}'`

那么程序可以很正常地kill掉。搞不明白到底是什么导致这种差异的产生。从Java的文档里也看不出什么东西来：

public Process exec(String[] cmdarray)
             throws IOException

Executes the specified command and arguments in a separate process.

This is a convenience method. An invocation of the form exec(cmdarray) behaves in exactly the same way as the invocation exec(cmdarray, null, null).

Parameters:

cmdarray - array containing the command to call and its arguments.

Returns:

A new Process object for managing the subprocess

Throws:

SecurityException - If a security manager exists and its checkExec method doesn't allow creation of the subprocess

IOException - If an I/O error occurs

NullPointerException - If cmdarray is null, or one of the elements of cmdarray is null

IndexOutOfBoundsException - If cmdarray is an empty array (has length 0)

See Also:

ProcessBuilder

如果有谁知道原因，麻烦告知一声，非常感谢。