Caused by outdated/broken Java:

Please update your Java to the latest version (1.7.0_65 / 1.8.0_11): http://www.java.com/en/download/.

• When using a 32-bit browser on a 64-bit operating system the automatic version detection will only show the 32-bit version of Java, the 64-bit version needs to be downloaded manually: http://www.java.com/en/download/manual.jsp.

Please update your Java to the latest version

• Which Java version do I have? Is Minecraft using the lastest Java version?
  • Sometimes, you can have multiple versions of Java installed. To be sure of which one is used by Minecraft, open the Minecraft launcher, go to the "Launcher Log" tab, look for the line System.getProperty('java.version') == '1.X.0_YY' Where X = Java version (6, 7 or 8) and YY = update version (as of today, 65 is the lastest update for Java 7)

• How do I know which one is the lastest Java version avaible?
  • Go to http://www.java.com and click on the big red button "Free Java Download". In the next page you will see the message "Recommended version" followed by the lastest recommended version.

• 32 or 64 bit version?
  • Do you have a 64 bit operating system? Get the 64 bit version, Minecraft will run better that way (more so if you set up Minecraft to a far view distance).

• How do I know if I have a 64 bit operating system?
  • Open the Minecraft launcher, go to the "Launcher Log" tab, look for the line System.getProperty('os.arch') == 'XXXXX'. It will say 'x86' if your OS is 32bit and 'amd64' if is 64bit.

• How do I update to the lastest version of Java?
  • I recommend first uninstalling all the old versions you find on "add / remove programs" on the "control panel" to avoid the problem of a program using the wrong version. When there's no more Javas, continuie with one of the following lines:
  • If you have a 32 bit OS, go to http://www.java.com and click on the button "Free Java Download" and then the "Agree and begin Free Download", and follow the installer instructions*.
  • If you have a 64 bit OS, go to http://www.java.com/en/download/manual.jsp and click on "Windows Offline (64-bit)", and follow the installer instructions*.
  • *In both versions I highly recommend unticking the optional software bundled with Java, it's just bloatware without any real usefulness, and it isn't required in any way.

• I already have the lastest Java version and: I'm using the 64bit version or I'm using the 32bit one because my OS is 32 bit. Now what?
  • Try uninstalling the Java version you have installed and download and install the lastest version anyway; maybe your Java installation is damaged in some way. Use the same instructions of the previous question.