fix code

hutool-core/src/main/java/cn/hutool/core/util/ObjUtil.java

@@ -202,7 +202,7 @@ public class ObjUtil {
 	 * @return 是否为null
 	 */
 	public static boolean isNotNull(final Object obj) {
-		return false == isNull(obj);
+		return null != obj;
 	}
 
 	/**

hutool-core/src/test/java/cn/hutool/core/convert/ConverterRegistryTest.java

@@ -35,7 +35,7 @@ public class ConverterRegistryTest {
 
 	public static class CustomConverter implements Converter{
 		@Override
-		public Object convert(Type targetType, Object value) throws ConvertException {
+		public Object convert(final Type targetType, final Object value) throws ConvertException {
 			return "Custom: " + value.toString();
 		}
 	}