fix: BucketArgs.Builder.validate() to accept A type args

api/src/main/java/io/minio/BucketArgs.java

@@ -65,7 +65,7 @@ private void validateRegion(String region) {
     }
 
     @Override
-    protected void validate(BucketArgs args) {
+    protected void validate(A args) {
       validateName(args.bucketName);
       validateRegion(args.region);
     }

api/src/test/java/io/minio/MakeBucketArgsTest.java

@@ -0,0 +1,53 @@
+/*
+ * MinIO Java SDK for Amazon S3 Compatible Cloud Storage,
+ * (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.minio;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class MakeBucketArgsTest {
+  @Test(expected = IllegalArgumentException.class)
+  public void testEmptyBuild() {
+    MakeBucketArgs.builder().build();
+    Assert.fail("exception should be thrown");
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testEmptyBucketBuild1() {
+    MakeBucketArgs.builder().objectLock(false).build();
+    Assert.fail("exception should be thrown");
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testEmptyBucketBuild2() {
+    MakeBucketArgs.builder().bucket(null).build();
+    Assert.fail("exception should be thrown");
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testEmptyBucketBuild3() {
+    MakeBucketArgs.builder().bucket("mybucket").bucket(null).build();
+    Assert.fail("exception should be thrown");
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testEmptyRegionBuild() {
+    MakeBucketArgs.builder().region("").build();
+    Assert.fail("exception should be thrown");
+  }
+}