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Tag: java

Buttons not visible until mouseover

I created a frame and panel (for Graphics) and add buttons to the panel. However, when I run my program buttons are not visible until I hover over them. Maybe it is something wrong with graphics methods. How the problem can be solved? Answer Your painting code is mostly wrong. For example: If you need to over…

Runnable interface instantiation

I am following the book Head first java and was reading about threads and came to know about the Runnable interface. Now we know an interface can’t be instantiated directly. Its members are implemented by any class that implements the interface , but below code made bouncers over my head. The book decla…

Reading input from 2 files and writing to a third file in ascending order

I have 2 files that each contain a series of ordered numbers, separated by spaces (” “). Write a program that produces a third file that will contain the ascending sequence of numbers. When solving, you are not allowed to use any type of collection. File 1: 1 18 40 100 File 2: 0 10 15 80 1001 I ma…

Make method accept only parameter with particular annotation

I have a method And I have a class which holds field And I have main class, where I call that method and pass him that: Problem is that the method accepts all the 3 parameters, (no warnings, errors, nothing) however only roomDao is annotated. Annotation itself: How to make the restriction, so that injectConfi…