public Builder clearExecutionMode() {
        executionMode_ = getDefaultInstance().getExecutionMode();
        bitField0_ = (bitField0_ & ~0x00000008);
        onChanged();
        return this;
      }
<code>optional string executionMode = 4;</code>
@return This builder for chaining.
ql/src/gen/protobuf/gen-java/org/apache/hadoop/hive/ql/hooks/proto/HiveHookEvents.java