We also showed how to change the accessible flag on the reflected method objects to suppress Java access control checks when invoking private and protected methods. You can access a field of an object if you know the name of such field or you can call a method of the object. In this quick article, weve seen how to call instance and static methods of a class at runtime through reflection. Use this when you want to access static fields and methods on a Class object. Here is the result when calling the above method: System. The Java Reflection introduces another approach. Wrap an Object / Class / class name with the on() method: on(java.lang. This field is declared in the class “Test”, here is the method that let us modify this const variable : public static void changePiValue ( double newValue ) Let’s imagine you want to modify the value of the following field: // We won't test directly on Math.PI because it's a primitive var (double) // => so the JVM inlined it private static final Double PI = Double. Using basic Java code it’s impossible to change this value, you have to use Java Reflection API. Now, we use methods getClass and isAssignableFrom from Java Reflection to obtain an instance of representing the runtime classes of c and d. It was initialized once when this class has been loaded, then it wasn’t modifiable anymore. I had to do this because this field was initialized by a JVM argument. Get The Method: Next, we get the required methods from the. Previously I was working on a project with a lot of legacy code, one of my goals was to test parts of the “API”, in some cases I had to change the value of a “private static final” field. Create a Class Object: We create a Class Object of Type StudentDetails using the.
0 Comments
Leave a Reply. |