add java 8 to CI workflow (#194) (#197)

* add java 8 to CI workflow

Signed-off-by: Yaliang Wu <[email protected]>

* remove unused imports

Signed-off-by: Yaliang Wu <[email protected]>
(cherry picked from commit e4653c4)

Co-authored-by: Yaliang Wu <[email protected]>

Author: opensearch-trigger-bot[bot]

.github/workflows/CI-workflow.yml

@@ -11,7 +11,7 @@ jobs:
   Build-ml:
     strategy:
       matrix:
-        java: [11, 14]
+        java: [8, 11, 14]
 
     name: Build and Test MLCommons Plugin
     runs-on: ubuntu-latest

common/src/test/java/org/opensearch/ml/common/dataframe/DefaultDataFrameTest.java

@@ -10,16 +10,13 @@
 import java.util.List;
 import java.util.function.Function;
 
-import org.graalvm.compiler.lir.LIRInstruction;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentParser;