Refactor core-java (#2324)

core-java/src/main/java/com/baeldung/concurrent/cyclicbarrier/CyclicBarrierExample.java

@@ -19,7 +19,5 @@ public class CyclicBarrierExample {
             t2.start();
             t3.start();
         }
-
     }
-
 }

core-java/src/main/java/com/baeldung/concurrent/cyclicbarrier/Task.java

@@ -21,5 +21,4 @@ public class Task implements Runnable {
             e.printStackTrace();
         }
     }
-
 }

core-java/src/main/java/org/baeldung/equalshashcode/entities/Rectangle.java

@@ -4,7 +4,7 @@ public class Rectangle extends Shape {
     private double width;
     private double length;
 
-    public Rectangle(double width, double length) {
+    Rectangle(double width, double length) {
         this.width = width;
         this.length = length;
     }

core-java/src/main/java/org/baeldung/executable/ExecutableMavenJar.java

@@ -1,11 +1,10 @@
 package org.baeldung.executable;
 
-import javax.swing.JOptionPane;
+import javax.swing.*;
 
 public class ExecutableMavenJar {
 
     public static void main(String[] args) {
         JOptionPane.showMessageDialog(null, "It worked!", "Executable Jar with Maven", 1);
     }
-
 }