I am running the Java 7 JRE from Oracle. I installed it through terminal and it works properly with my web browsers, and otherwise, as far as I can tell.

However, I was browsing through my installed packages in Software Center, and noticed that both the openjdk-7-jre-lib Install openjdk-7-jre-lib and openjdk-7-jre-headless Install openjdk-7-jre-headless packages were still installed from when I had the OpenJKD JRE installed, which I have since uninstalled, but did use for a good period of time before I switched.

Should those be there, or might they cause complications if I leave them installed? Or would it be best to leave them installed?

2 Answers 2


It won't do any harm if you leave them installed. If you do decide to uninstall them (because I don't think they're needed since you're using Oracle's JRE), make sure it does not offer to uninstall other important packages with them.


You could remove OpenJDK JRE without any problem or leave it just the same.

Java is a technology from Oracle (formerly: Sun Microsystems). There are several implementations:

  1. OpenJDK: The primary goal of the OpenJDK project is to produce an open-source implementation of the Java SE Platform (6 and 7). This is the default version of Java that Ubuntu uses and is the easiest to install.

  2. Oracle (Sun) Java 6: Oracle (Sun) Java 6 is the reference implementation for Java 6.

  3. Oracle Java 7: Oracle Java 7 is the reference implementation for Java 7.

  4. IBM Java: IBM Java is the preferred Java solution on PowerPC machines. It is a reimplementation with a Just-In-Time Compiler. It is only available from IBM's website.

To manage your Java version/flavour in terminal use update-alternatives, to list the available java versions update-alternatives --list java.

If you'd wish all could be installed without issues, and you could choose witch one to use using update-alternatives --config java**

Please take note that java as four components, they must all be configured to you preference.

  1. java Java Runtime Environment (JRE);
  2. javaws Java Web Start, Java application over the net;
  3. javac Java Compiler, JDK for Developers;
  4. And of course the browser plugin, currently mine is libnpjp2.so with firefox is easy to find out yours just type about:plugins in the address bar.

Normally the several java flavors/versions are in /usr/lib/jvm, me, for example have OpenJDK and two different versions of Oracle-Java.

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