Cant figure out whats wrong with this very simple code?

public class worker {

public static void main(String[] args){

//read in the file into string array of words

String[] commands = {"a","b","c"};

for(int i = 0; i<= commands.length; i++){

if (commands[i] == "a") {

System.out.print(commands[i]);

}

else if (commands[i] == "b") {

System.out.print(commands[i]);

}

else if (commands[i] == "c") {

System.out.print(commands[i]);

}

else{

System.out.print("none of these was found!");

}

}

}

}