Conversion of a String to code

Question

Hopefully this is phrased in such a way that it can be understandable and answered; how would one convert a String object to code? For example say a program had a user enter a class name and a method from a class, is there a means by which the text entered could be used as code? So if someone entered, "Math.abs(-1)" is it possible to derive from that the abs method and or the Math class?

Answer 1

There are other ways: you could use Groovy:
// To run this demo,
// download Groovy: http://groovy.codehaus.org/Download
// and stick the file 'groovy-all-1.6.3.jar' in your classpath.
public class GroovyDemo {
    public static void main(String[] args) {
        groovy.lang.GroovyShell shell = new groovy.lang.GroovyShell();
        System.out.println(shell.evaluate("Math.abs(-1)")); // output: 1
}Note that you can compile any Java-method, -statement or -source file with the GroovyShell.