remove the level setting

binding/java/pom.xml

@@ -112,14 +112,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>8</source>
-                    <target>8</target>
-                </configuration>
-            </plugin>
         </plugins>
     </build>
 

binding/java/src/main/java/org/lionsoul/ip2region/SearchTest.java

@@ -9,6 +9,7 @@ package org.lionsoul.ip2region;
 import org.lionsoul.ip2region.xdb.Searcher;
 
 import java.io.*;
+import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.concurrent.TimeUnit;