Fixes #364 construct bob in setUp

exercises/bob/src/test/java/BobTest.java

@@ -1,12 +1,18 @@
 import org.junit.Test;
 import org.junit.Ignore;
+import org.junit.Before;
 
 import static org.junit.Assert.*;
 
 public class BobTest {
-    private final Bob bob = new Bob();
+    private Bob bob;
 
 
+    @Before
+    public void setUp() {
+        bob = new Bob();
+    }
+
     @Test
     public void saySomething() {
         assertEquals(