diff --git a/arthas-vmtool/README_CN.md b/arthas-vmtool/README_CN.md
deleted file mode 100644
index 4ea4b8795..000000000
--- a/arthas-vmtool/README_CN.md
+++ /dev/null
@@ -1,62 +0,0 @@
-##step1 在您的pom.xml中增加profile配置
-```
-<profiles>
-    <!-- macos -->
-    <profile>
-        <id>macos</id>
-        <activation>
-            <os>
-                <family>mac</family>
-            </os>
-        </activation>
-        <properties>
-            <os_family>macos</os_family>
-        </properties>
-    </profile>
-
-    <!-- linux -->
-    <profile>
-        <id>linux</id>
-        <activation>
-            <os>
-                <name>linux</name>
-            </os>
-        </activation>
-        <properties>
-            <os_family>linux</os_family>
-        </properties>
-    </profile>
-    
-    <!-- windows -->
-    <profile>
-        <id>windows</id>
-        <activation>
-            <os>
-                <family>windows</family>
-            </os>
-        </activation>
-        <properties>
-            <os_family>windows</os_family>
-        </properties>
-    </profile>
-</profiles>
-```
-##step2 在您的pom.xml中引入依赖
-PS：一定要配置好profile，不然无法自动生成`<classifier>`配置。
-```
-<dependency>
-    <groupId>com.taobao.arthas</groupId>
-    <artifactId>mana-pool-analyzer</artifactId>
-    <version>${arthas.vision}</version>
-    <classifier>${os_family}-${os.arch}</classifier>
-</dependency>
-```
-
-##step3 如果没有合适的版本
-1. 如果是32位的操作系统，不好意思，目前暂不支持。
-
-2. 如果是64位操作系统，请先尝试`mvn clean compile package install -DskipTests=true -U`把依赖安装到本地；
-
-3. 如果报错，请先确保您本地的g++编译器能够正常工作，再重新尝试`mvn clean compile package install -DskipTests=true -U`；
-
-如有问题请联系`1936978077@qq.com`。
diff --git a/core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java b/core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java
index 35e46ec0e..6f7dd468d 100644
--- a/core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java
+++ b/core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java
@@ -48,7 +48,9 @@ import arthas.VmTool;
         + "  vmtool --action getInstances --className demo.MathGame\n"
         + "  vmtool --action getInstances --className demo.MathGame --express 'instances.length'\n"
         + "  vmtool --action getInstances --className demo.MathGame --express 'instances[0]'\n"
+        + "  vmtool --action getInstances --className demo.MathGame -x 2\n"
         + "  vmtool --action getInstances --className java.lang.String --limit 10\n"
+        + "  vmtool --action getInstances --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader --className org.springframework.context.ApplicationContext\n"
         + "  vmtool --action forceGc\n"
         + Constants.WIKI + Constants.WIKI_HOME + "vmtool")
 //@formatter:on
@@ -62,7 +64,7 @@ public class VmToolCommand extends AnnotatedCommand {
     private String hashCode = null;
     private String classLoaderClass;
     /**
-     * default value 2
+     * default value 1
      */
     private int expand;
 
@@ -107,8 +109,8 @@ public class VmToolCommand extends AnnotatedCommand {
     }
 
     @Option(shortName = "x", longName = "expand")
-    @Description("Expand level of object (2 by default)")
-    @DefaultValue("2")
+    @Description("Expand level of object (1 by default)")
+    @DefaultValue("1")
     public void setExpand(int expand) {
         this.expand = expand;
     }
@@ -154,6 +156,10 @@ public class VmToolCommand extends AnnotatedCommand {
             Instrumentation inst = process.session().getInstrumentation();
 
             if (VmToolAction.getInstances.equals(action)) {
+                if (className == null) {
+                    process.end(-1, "The className option cannot be empty!");
+                    return;
+                }
                 ClassLoader classLoader = ClassLoader.getSystemClassLoader();
                 if (hashCode == null && classLoaderClass != null) {
                     List<ClassLoader> matchedClassLoaders = ClassLoaderUtils.getClassLoaderByClassName(inst,
@@ -177,7 +183,7 @@ public class VmToolCommand extends AnnotatedCommand {
                 }
 
                 List<Class<?>> matchedClasses = new ArrayList<Class<?>>(
-                        SearchUtils.searchClass(inst, className, false, hashCode));
+                        SearchUtils.searchClassOnly(inst, className, false, hashCode));
                 int matchedClassSize = matchedClasses.size();
                 if (matchedClassSize == 0) {
                     process.end(-1, "Can not find class by class name: " + className + ".");