Straightforward java compilation on termux

To run java apps on your android device, install termux, and run the following:

$ pkg install ecj dx
$ cat > Hello.java <<EOF
public class Hello {
  public static void main(String[] args) {
    System.out.println("Hello world, on termux!");
  }
}
EOF
$ ecj Hello.java
$ dx --dex --output=Hello.dex Hello.class
$ dalvikvm -cp Hello.dex Hello
Hello world, on termux!