diff --git a/ksql-core/src/main/java/io/confluent/ksql/function/KsqlAggFunctionDeterminer.java b/ksql-core/src/main/java/io/confluent/ksql/function/KsqlAggFunctionDeterminer.java
index a75c8951c247..f6b7964c0b8f 100644
--- a/ksql-core/src/main/java/io/confluent/ksql/function/KsqlAggFunctionDeterminer.java
+++ b/ksql-core/src/main/java/io/confluent/ksql/function/KsqlAggFunctionDeterminer.java
@@ -17,7 +17,6 @@
 package io.confluent.ksql.function;
 
 import org.apache.kafka.connect.data.Schema;
-import org.apache.kafka.streams.kstream.Merger;
 
 import java.util.List;
 
diff --git a/ksql-core/src/main/java/io/confluent/ksql/function/KsqlFunctions.java b/ksql-core/src/main/java/io/confluent/ksql/function/KsqlFunctions.java
index d39000eb7f0d..8641eb281d62 100644
--- a/ksql-core/src/main/java/io/confluent/ksql/function/KsqlFunctions.java
+++ b/ksql-core/src/main/java/io/confluent/ksql/function/KsqlFunctions.java
@@ -169,10 +169,7 @@ public static void addFunction(KsqlFunction ksqlFunction) {
   }
 
   public static boolean isAnAggregateFunction(String functionName) {
-    if (ksqlAggregateFunctionMap.get(functionName) != null) {
-      return true;
-    }
-    return false;
+    return ksqlAggregateFunctionMap.get(functionName) != null;
   }
 
   public static KsqlAggregateFunction getAggregateFunction(String functionName, List<Expression>
diff --git a/ksql-core/src/main/java/io/confluent/ksql/metastore/MetastoreUtil.java b/ksql-core/src/main/java/io/confluent/ksql/metastore/MetastoreUtil.java
index 109fc09d0b6a..7c43a66d6c74 100644
--- a/ksql-core/src/main/java/io/confluent/ksql/metastore/MetastoreUtil.java
+++ b/ksql-core/src/main/java/io/confluent/ksql/metastore/MetastoreUtil.java
@@ -154,8 +154,6 @@ private String getKsqlTypeInJson(final Schema schemaType) {
       return "STRING";
     } else if (schemaType == Schema.FLOAT64_SCHEMA) {
       return "DOUBLE";
-    } else if (schemaType == Schema.INT64_SCHEMA) {
-      return "INTEGER";
     } else if (schemaType == Schema.BOOLEAN_SCHEMA) {
       return "BOOL";
     }
@@ -276,8 +274,7 @@ public void writeMetastoreToFile(String filePath, MetaStore metaStore) {
     addSchemas(stringBuilder, metaStore.getAllStructuredDataSources());
     stringBuilder.append("}");
 
-    try {
-      RandomAccessFile raf = new RandomAccessFile(filePath, "rw");
+    try (RandomAccessFile raf = new RandomAccessFile(filePath, "rw")) {
       raf.writeBytes(stringBuilder.toString());
       raf.close();
     } catch (IOException e) {
@@ -301,8 +298,7 @@ private String getAvroSchema(final String schemaFilePath) throws IOException {
 
   public void writeAvroSchemaFile(final String avroSchema, final String filePath) {
 
-    try {
-      RandomAccessFile randomAccessFile = new RandomAccessFile(filePath, "rw");
+    try (RandomAccessFile randomAccessFile = new RandomAccessFile(filePath, "rw")) {
       randomAccessFile.writeBytes(avroSchema);
       randomAccessFile.close();
     } catch (IOException e) {
diff --git a/ksql-core/src/main/java/io/confluent/ksql/util/SchemaUtil.java b/ksql-core/src/main/java/io/confluent/ksql/util/SchemaUtil.java
index 359d2e69472e..d5aba938ca00 100644
--- a/ksql-core/src/main/java/io/confluent/ksql/util/SchemaUtil.java
+++ b/ksql-core/src/main/java/io/confluent/ksql/util/SchemaUtil.java
@@ -104,7 +104,7 @@ public static int getFieldIndexByName(final Schema schema, final String fieldNam
     }
     for (int i = 0; i < schema.fields().size(); i++) {
       Field field = schema.fields().get(i);
-      int dotIndex = field.name().indexOf(".");
+      int dotIndex = field.name().indexOf('.');
       if (dotIndex == -1) {
         if (field.name().equals(fieldName)) {
           return i;
@@ -189,7 +189,7 @@ public static synchronized Schema removeImplicitRowTimeRowKeyFromSchema(Schema s
     SchemaBuilder schemaBuilder = SchemaBuilder.struct();
     for (Field field: schema.fields()) {
       String fieldName = field.name();
-      fieldName = fieldName.substring(fieldName.indexOf(".") + 1);
+      fieldName = fieldName.substring(fieldName.indexOf('.') + 1);
       if (!fieldName.equalsIgnoreCase(SchemaUtil.ROWTIME_NAME)
           && !fieldName.equalsIgnoreCase(SchemaUtil.ROWKEY_NAME)) {
         schemaBuilder.field(fieldName, field.schema());