public class permutation{

	public static void main(String[] args) {
	        permutation(new String("STJ"));
	}

	public static void permutation(String str) {
		char[] in = str.toCharArray();
		perm(in, 0);
	}

	void perm(char[] in, int start) {
		if (start == in.length - 1) {
		         System.out.println(String.valueOf(in));
		} else {
			for (int i = start; i < in.length; i++) {
				move(in, start, i);    
				perm(in, start + 1);
				move(in, start, i);
			}
		}
	}

	void move(char[] in, int first, int second) {
		char temp;
		temp = in[first];
		in[first] = in[second];
		in[second] = temp;
	}

}

 输出结果：

STJ
SJT
TSJ
TJS
JTS
JST