Dynamic Java Code?

Question

Is there a way to compose dynamic java code?
For example in PL/SQL I can compose valid statement dynamicly on runtime on base of string variables, execute it and get the result:
execute immediate ' SELET * FROM dual'Let's say, in Java I accept simple arithmetic statement from console 4+2. If I will pass it to System.out.print, then I get echo of this statement:
System.out.print(arg[0]);but result is different if I do following:
System.out.print(4+2);So I would like to see the way to compose the System.out.print(4+2) dynamicly within the code on base of string variables and execute it.
Any opinions?

Answer 1

For that, it is easy to use the scripting engine. Demo:
import javax.script.*;
public class ScriptTest {
    public static void main(String[] args) throws ScriptException {
            ScriptEngineManager man = new ScriptEngineManager();
            ScriptEngine engine = man.getEngineByExtension("groovy");
            if (engine == null) {
                System.out.println("no groovy engine");
            } else {
                System.out.println("engine found");
                String s = "x=[1, 4, 9, 16]; x.collect {it-1}";
                Object result = engine.eval(s);
                System.out.println("result : " + result);
}This assumes the groovy jar is on classpath.