Apache Commons JEXL

Apache Commons JEXL (Java Expression Language)
JEXL Syntax

//-- Main.java --
import org.apache.commons.jexl2.Expression;
import org.apache.commons.jexl2.JexlContext;
import org.apache.commons.jexl2.JexlEngine;
import org.apache.commons.jexl2.MapContext;

public class Main {

  public static void main(String[] args) throws Exception {
    // Create or retrieve a JexlEngine
    JexlEngine jexl = new JexlEngine();
    // Create an expression object
    String jexlExp = "if ((x * 2) == 5) { y = 1; } else {y = 2;}";
    Expression e = jexl.createExpression(jexlExp);

    // Create a context and add data
    JexlContext jc = new MapContext();
    jc.set("x", 2.5);

    // Now evaluate the expression, getting the result
    Object o = e.evaluate(jc);
    System.out.println(o);
  }

}