a java tips like "shell_exec()" on PHP.

shell_exec.java

try {
	Process ps = Runtime.getRuntime().exec("ps");
	  
	BufferedReader reader = new BufferedReader(new InputStreamReader(ps.getInputStream()));
	int read;
	char[] buffer = new char[4096];
	StringBuffer output = new StringBuffer();
	
	while ((read = reader.read(buffer)) > 0) {
		output.append(buffer, 0, read);
	}
	reader.close();
		   
	// Waits for the command to finish.
	ps.waitFor(); 
	    
	System.out.println(output.toString());

} catch (IOException e) {
	e.printStackTrace();
} catch (InterruptedException e) {
	e.printStackTrace();
}
finally {
	ps.destroy();
}