[RocksJava] Incoroporated changes for D29013

java/org/rocksdb/ColumnFamilyOptions.java

@@ -128,7 +128,10 @@ public class ColumnFamilyOptions extends RocksObject
   @Override
   public ColumnFamilyOptions setMergeOperatorName(String name) {
     assert (isInitialized());
-    assert (name != null);
+    if (name == null) {
+      throw new IllegalArgumentException(
+          "Merge operator name must not be null.");
+    }
     setMergeOperatorName(nativeHandle_, name);
     return this;
   }

java/org/rocksdb/Options.java

@@ -166,7 +166,10 @@ public class Options extends RocksObject
   @Override
   public Options setMergeOperatorName(String name) {
     assert (isInitialized());
-    assert (name != null);
+    if (name == null) {
+      throw new IllegalArgumentException(
+          "Merge operator name must not be null.");
+    }
     setMergeOperatorName(nativeHandle_, name);
     return this;
   }

java/org/rocksdb/test/MergeTest.java

@@ -273,7 +273,7 @@ public class MergeTest {
     }
   }
 
-  @Test(expected = AssertionError.class)
+  @Test(expected = IllegalArgumentException.class)
   public void nullStringInSetMergeOperatorByNameOptions() {
     Options opt = null;
     try {
@@ -286,7 +286,7 @@ public class MergeTest {
     }
   }
 
-  @Test(expected = AssertionError.class)
+  @Test(expected = IllegalArgumentException.class)
   public void
       nullStringInSetMergeOperatorByNameColumnFamilyOptions() {
     ColumnFamilyOptions opt = null;