Can't open ddms

I am using ubuntu 14.04 LTS to build android using command line. However, after I open the emulator, trying to open ddms. I got the following error message

09:36:10 E / ddms: shutdown due to uncaught exception 09:36:10 E / ddms: org / eclipse / jface / util / IPropertyChangeListener java.lang.NoClassDefFoundError: org / eclipse / jface / util / IPropertyChangeListener in com .android.ddms.Main.main (Main.java:74) Thrown by: java.lang.ClassNotFoundException: org.eclipse.jface.util.IPropertyChangeListener at java.net.URLClassLoader $ 1.run (URLClassLoader.java:366) in java .net.URLClassLoader $ 1.run (URLClassLoader.java:355) in java.security.AccessController.doPrivileged (native method) in java.net.URLClassLoader.findClass (URLClassLoader.java:354) in java.lang.ClassLoader.loadClass ( ClassLoader.java:425) at sun.misc.Launcher $ AppClassLoader.loadClass (Launcher.java.308) at java.lang.ClassLoader.loadClass (ClassLoader.java:358) ... 1 more

It seems that the class was not found. But I'm not sure what exactly this means. After searching, I found that it might be wrong ANDROID_SWT. However, after checking, the same problem still exists.

Any idea can help! Thank!