Two project requirements are different, need different jdk (1.7,1.8), so each time you switch the project will be re-uninstall the original, in the installation of new, more trouble.
Check the data. You can install multiple JDK at the same time, but only one environment variable is configured at a time. The installation of the time still encountered a problem.
First installed 1.8, then installed 1.7, also in the environment variable 1.7
Java_home:d:\neatbeanssofts\java\jdk1.7.0_45
ClassPath:.; %java_home%\lib;%java_home%\lib\tools.jar
Path:%java_home%\bin;%java_home%\jre\bin;
Locate the directory C:\Windows\System32 and delete the Java.exe,javaw.exe,javaws.exe
But still no, cmd execution java-version display or 1.8 version of the
Then put the configuration information in the path Java_home in the first place,
Re-executing the java-version will show 1.7.
Complete.
Windows installs two JDK at a time