fix checkstyle

Author: strongduanmu

core/src/test/java/org/apache/calcite/test/JdbcTest.java

@@ -9070,12 +9070,14 @@ void checkCalciteSchemaGetSubSchemaMap(boolean cache) {
 
   /** Test case for
    * <a href="https://issues.apache.org/jira/browse/CALCITE-5094">[CALCITE-5094]
-   * Calcite JDBC Adapter and Avatica should support MySQL UNSIGNED types of TINYINT, SMALLINT, INT, BIGINT</a>. */
+   * Calcite JDBC Adapter and Avatica should support
+   * MySQL UNSIGNED types of TINYINT, SMALLINT, INT, BIGINT</a>. */
   @Test void testMySQLUnsignedType() {
     CalciteAssert.that()
         .with(CalciteAssert.SchemaSpec.UNSIGNED_TYPE)
         .with(Lex.MYSQL)
-        .query("SELECT * FROM test_unsigned WHERE tiny_id = ? AND small_id = ? AND int_id = ? AND big_id = ?")
+        .query("SELECT * FROM test_unsigned WHERE tiny_id = ? "
+            + "AND small_id = ? AND int_id = ? AND big_id = ?")
         .consumesPreparedStatement(p -> {
           p.setInt(1, 255);
           p.setInt(2, 65535);

linq4j/src/main/java/org/apache/calcite/linq4j/tree/UnsignedType.java

@@ -16,8 +16,6 @@
  */
 package org.apache.calcite.linq4j.tree;
 
-import com.google.common.base.Preconditions;
-
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.joou.UByte;
 import org.joou.UInteger;
@@ -30,6 +28,8 @@
 import java.math.BigInteger;
 import java.math.RoundingMode;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 /** Support for compiling unsigned types.
  * This class has a role similar to {@link Primitive} */
 public enum UnsignedType {
@@ -112,7 +112,7 @@ public static UByte toUByte(double n) {
   }
 
   public static UByte toUByte(Object n) {
-    Preconditions.checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
+    checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
     return toUByteNonNull((Number) n, RoundingMode.DOWN);
   }
 
@@ -171,7 +171,7 @@ public static UShort toUShort(double n) {
   }
 
   public static UShort toUShort(Object n) {
-    Preconditions.checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
+    checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
     return toUShortNonNull((Number) n, RoundingMode.DOWN);
   }
 
@@ -234,7 +234,7 @@ public static UInteger toUInteger(double n) {
   }
 
   public static UInteger toUInteger(Object n) {
-    Preconditions.checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
+    checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
     return toUIntegerNonNull((Number) n, RoundingMode.DOWN);
   }
 
@@ -293,7 +293,7 @@ public static ULong toULong(double n) {
   }
 
   public static ULong toULong(Object n) {
-    Preconditions.checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
+    checkArgument(n instanceof Number, "Unexpected Object value " + n.getClass().getSimpleName());
     return toULongNonNull((Number) n, RoundingMode.DOWN);
   }
 

testkit/src/main/java/org/apache/calcite/test/CalciteAssert.java

@@ -2366,12 +2366,12 @@ static List<String> unwrap(String java) {
   /** Schema instance for {@link SchemaSpec#UNSIGNED_TYPE}. */
   private static final Schema UNSIGNED_TYPE_SCHEMA = new AbstractSchema() {
 
-    @Override
-    protected Map<String, Table> getTableMap() {
+    @Override protected Map<String, Table> getTableMap() {
       return ImmutableMap.of("test_unsigned", new UnsingedScannableTable());
     }
   };
 
+  /** Scannable table for unsigned types test. */
   private static class UnsingedScannableTable extends AbstractTable implements ScannableTable {
 
     /**