check vm java version before attach. fixed #6

core/src/main/java/com/taobao/arthas/core/Arthas.java

@@ -3,6 +3,7 @@ package com.taobao.arthas.core;
 import com.sun.tools.attach.VirtualMachine;
 import com.sun.tools.attach.VirtualMachineDescriptor;
 import com.taobao.arthas.core.config.Configure;
+import com.taobao.arthas.core.util.AnsiLog;
 import com.taobao.middleware.cli.CLI;
 import com.taobao.middleware.cli.CLIs;
 import com.taobao.middleware.cli.CommandLine;
@@ -10,6 +11,7 @@ import com.taobao.middleware.cli.Option;
 import com.taobao.middleware.cli.TypedOption;
 
 import java.util.Arrays;
+import java.util.Properties;
 
 /**
  * Arthas启动器
@@ -59,7 +61,6 @@ public class Arthas {
                 virtualMachineDescriptor = descriptor;
             }
         }
-
         VirtualMachine virtualMachine = null;
         try {
             if (null == virtualMachineDescriptor) { // 使用 attach(String pid) 这种方式
@@ -67,6 +68,19 @@ public class Arthas {
             } else {
                 virtualMachine = VirtualMachine.attach(virtualMachineDescriptor);
             }
+
+            Properties targetSystemProperties = virtualMachine.getSystemProperties();
+            String targetJavaVersion = targetSystemProperties.getProperty("java.specification.version");
+            String currentJavaVersion = System.getProperty("java.specification.version");
+            if (targetJavaVersion != null && currentJavaVersion != null) {
+                if (!targetJavaVersion.equals(currentJavaVersion)) {
+                    AnsiLog.warn("Current VM java version: {} do not match target VM java version: {}, attach may fail.",
+                                    currentJavaVersion, targetJavaVersion);
+                    AnsiLog.warn("Target VM JAVA_HOME is {}, try to set the same JAVA_HOME.",
+                                    targetSystemProperties.getProperty("java.home"));
+                }
+            }
+
             virtualMachine.loadAgent(configure.getArthasAgent(),
                             configure.getArthasCore() + ";" + configure.toString());
         } finally {
@@ -81,7 +95,7 @@ public class Arthas {
         try {
             new Arthas(args);
         } catch (Throwable t) {
-            System.err.println("Start arthas failed, exception stack trace: ");
+            AnsiLog.error("Start arthas failed, exception stack trace: ");
             t.printStackTrace();
             System.exit(-1);
         }

core/src/main/java/com/taobao/arthas/core/util/AnsiLog.java

@@ -0,0 +1,77 @@
+package com.taobao.arthas.core.util;
+import java.util.regex.Matcher;
+
+/**
+ *
+ * @author hengyunabc 2017-05-03
+ *
+ */
+public abstract class AnsiLog {
+
+    static boolean enable = System.console() != null;
+
+    /**
+     *
+     * @param msg
+     */
+    public static void red(String msg) {
+        if (enable) {
+            System.out.println("" + msg + "");
+        } else {
+            System.err.println(msg);
+        }
+    }
+
+    public static void green(String msg) {
+        if (enable) {
+            System.out.println("" + msg + "");
+        } else {
+            System.out.println(msg);
+        }
+    }
+
+    public static void yellow(String msg) {
+        if (enable) {
+            System.out.println("" + msg + "");
+        } else {
+            System.out.println(msg);
+        }
+    }
+
+    public static void info(String msg) {
+        green(msg);
+    }
+
+    public static void info(String format, Object... arguments) {
+        green(format(format, arguments));
+    }
+
+    public static void warn(String msg) {
+        yellow(msg);
+    }
+
+    public static void warn(String format, Object... arguments) {
+        yellow(format(format, arguments));
+    }
+
+    public static void error(String msg) {
+        red(msg);
+    }
+
+    public static void error(String format, Object... arguments) {
+        red(format(format, arguments));
+    }
+
+    private static String format(String from, Object... arguments) {
+        if (from != null) {
+            String computed = from;
+            if (arguments != null && arguments.length != 0) {
+                for (Object argument : arguments) {
+                    computed = computed.replaceFirst("\\{\\}", Matcher.quoteReplacement(argument.toString()));
+                }
+            }
+            return computed;
+        }
+        return null;
+    }
+}