Dataset<Row> logDataFrame = spark.createDataFrame(rowRDD, schema);

    if (spark.catalog().tableExists("mylogs")) {
      logDataFrame.write().mode("append").insertInto("mylogs");// exception

    } else {
        logDataFrame.createOrReplaceTempView("mylogs"); // This is working fine
    }

    Dataset<Row> results = spark.sql("SELECT count(a1) FROM mylogs");

Exception in thread "main" org.apache.spark.sql.AnalysisException: unresolved operator 'InsertIntoTable LogicalRDD [a1#4, b1#5, c1#6, d1#7], false, false, false;;
'InsertIntoTable LogicalRDD [a1#4, b1#5, c1#6, d1#7], false, false, false
+- LogicalRDD [a1#22, b1#23, c1#24, d1#25], false

    at org.apache.spark.sql.catalyst.analysis.CheckAnalysis$class.failAnalysis(CheckAnalysis.scala:41)
    at org.apache.spark.sql.catalyst.analysis.Analyzer.failAnalysis(Analyzer.scala:91)
    at org.apache.spark.sql.catalyst.analysis.CheckAnalysis$$anonfun$checkAnalysis$3.apply(CheckAnalysis.scala:352)
    at org.apache.spark.sql.catalyst.analysis.CheckAnalysis$$anonfun$checkAnalysis$3.apply(CheckAnalysis.scala:350)

Dataset<Row> logDataFrame = sparkSession.createDataFrame(rowRDD, schema);

    if (sparkSession.catalog().tableExists("mylogs")) {
        logDataFrame.registerTempTable("temptable");
        sparkSession.sql("insert into table mylogs select * from temptable");
       //logDataFrame.write().mode(SaveMode.Append).insertInto("mylogs");
    } else {
        logDataFrame.createOrReplaceTempView("mylogs");
    }

    Dataset<Row> results = sparkSession.sql("SELECT count(a1) FROM mylogs");

Exception in thread "main" org.apache.spark.sql.AnalysisException: unresolved operator 'InsertIntoTable LogicalRDD [a1#4, b1#5, c1#6, d1#7], false, false, false;;
'InsertIntoTable LogicalRDD [a1#4, b1#5, c1#6, d1#7], false, false, false
+- Project [a1#22, b1#23, c1#24, d1#25]
   +- SubqueryAlias temptable
      +- LogicalRDD [a1#22, b1#23, c1#24, d1#25], false

    at org.apache.spark.sql.catalyst.analysis.CheckAnalysis$class.failAnalysis(CheckAnalysis.scala:41)
    at org.apache.spark.sql.catalyst.analysis.Analyzer.failAnalysis(Analyzer.scala:91)

logDataFrame.registerTempTable("temptable")

sqlContext.sql("insert into table mylogs select * from temptable"")