Fix flaky test caused by .toArray() (#403)

Author: bmk15897

apm-commons/apm-util/src/test/java/org/apache/skywalking/apm/util/ConfigInitializerTest.java

@@ -21,6 +21,7 @@
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.internal.util.collections.Sets;
 
 import java.util.Arrays;
 import java.util.HashMap;
@@ -67,8 +68,8 @@ public void testInitialize() throws IllegalAccessException {
         Assert.assertArrayEquals(new Integer[]{1, 2, 3, 4}, TestPropertiesObject.Level1Object.LIST_INT_ATTR_ED2.toArray());
         Assert.assertArrayEquals(new String[]{}, TestPropertiesObject.Level1Object.SET_STR_EMPTY_ATTR.toArray());
         Assert.assertArrayEquals(new Boolean[]{true, false}, TestPropertiesObject.Level1Object.LIST_BOOL_ATTR.toArray());
-        Assert.assertArrayEquals(new String[]{"a", "b", "c", "d"}, TestPropertiesObject.Level1Object.SET_STR_ATTR.toArray());
-        Assert.assertArrayEquals(new Integer[]{1, 2, 3, 4}, TestPropertiesObject.Level1Object.SET_INT_ATTR.toArray());
+        Assert.assertEquals(Sets.newSet("a", "b", "c", "d"), TestPropertiesObject.Level1Object.SET_STR_ATTR);
+        Assert.assertEquals(Sets.newSet(1, 2, 3, 4), TestPropertiesObject.Level1Object.SET_INT_ATTR);
         Assert.assertArrayEquals(new Boolean[]{true}, TestPropertiesObject.Level1Object.SET_BOOL_ATTR.toArray());
         Assert.assertEquals(TestColorEnum.RED, TestPropertiesObject.Level1Object.Level2Object.ENUM_ATTR);
         //make sure that when descs is empty,toString() work right;