Java:Runtime.getRuntime().exec(cmd) error with some commands,but works with other command

Question

This is my code:

public static void main(String[] args) throws Exception { String[] cmd = {"which", "hive"}; Process proc = Runtime.getRuntime().exec(cmd); BufferedReader reader = new BufferedReader( new InputStreamReader( proc.getInputStream() ) ); String line = ""; while((line = reader.readLine()) != null) { System.out.print(line + "\n"); } proc.waitFor(); }

In my terminal:

which hive:/home/as/hive/bin/hive which gcc:/usr/bin/gcc

But when I run this java code:

which hive:no result which gcc:/usr/bin/gcc

I've added $HIVE_HOME into ~/.bashrc (I'm using Ubuntu 14.04 64 bit and Java 8), so what should I do now?

If you want to see errors, I suggest you read the error stream. Or you can combine the two streams into one to make it easier to read. — Peter Lawrey
– Peter Lawrey, Commented Dec 13, 2014 at 13:48
How are you running Java? Are you sure hive is in your PATH when you run Java? Try printing System.out.println(System.getenv().get("PATH")); — Peter Lawrey
– Peter Lawrey, Commented Dec 13, 2014 at 13:52

Erwin Bolwidt · Accepted Answer · 2014-12-13 13:56:26Z

1

The command which looks in all the directories specified in the environment variable PATH. On Linux, the directories are separated by a colon (:) and on Windows by a semicolon (;).

You can check what PATH is being passed to which by doing a

System.out.println(System.getenv("PATH"));

And you can pass a different path to Runtime.exec:

String[] env = { "PATH=/home/as/hive/bin" }; Process proc = Runtime.getRuntime().exec(cmd, env);

If you do that, it which will find the hive command (but it will not longer find gcc unless you also add /usr/bin to the PATH, as in PATH=/home/as/hive/bin:/usr/bin)

answered Dec 13, 2014 at 13:56

Erwin Bolwidt

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3 Comments

voxter Over a year ago

as@ubuntu:~$ echo $PATH; /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/as/bin:/home/as/jdk1.8.0_25/bin:/home/as/hadoop/bin:/home/as/hadoop/sbin:/home/as/bin:/home/as/jdk1.8.0_25/bin:/home/as/sqoop-1.4.5.bin__hadoop-2.0.4-alpha/bin:/home/as/hbase/bin:/home/as/hive/bin

voxter Over a year ago

in java: System.out.println(System.getenv().get("PATH")); result: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/as/bin:/home/as/jdk1.8.0_25/bin

Erwin Bolwidt Over a year ago

On my machine, the java binary takes the path that was in $PATH when you start Java. If it's different on your machine, then you have a Unix (probably Linux) issue, possibly with the way you start Java, or maybe you started your application from your .profile before you set the PATH. It's hard to tell without a lot more information (and probably out of scope for SO). But as an immediate resolution/workaround, you can add to your PATH within Java (by passing an env variable to exec)

voxter · Accepted Answer · 2014-12-14 10:40:57Z

in my terminal:
as@ubuntu:~$ echo $PATH;
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/as/bin:/home/as/jdk1.8.0_25/bin:/home/as/hadoop/bin:/home/as/hadoop/sbin:/home/as/bin:/home/as/jdk1.8.0_25/bin:/home/as/sqoop-1.4.5.bin__hadoop-2.0.4-alpha/bin:/home/as/hbase/bin:/home/as/hive/bin
but in java:
System.out.println(System.getenv().get("PATH"));

Result:
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/as/bin:/home/as/jdk1.8.0_25/bin
so this is $PATH of my account with $PATH of root?
so how to fix it?

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