Shulou(Shulou.com)06/02 Report--

As the computer installed myeclipse2017, but also installed idea2017,idea is the latest version, must use more than jdk1.8, and the project in myeclipse requires a lower version of jdk, so in the computer before the installation of jdk1.8, and later to install jdk1.7, you can switch back and forth, but encountered a lot of problems in the process, sum up.

After installing jdk, we configure the environment variables and pay special attention to one problem:

With regard to the problem of changing environmental variables, I searched a lot of solutions, tried them one by one, and finally solved them. The main solutions are as follows:

1. In order to switch from jdk1.8 to 1.7, the first thing to do is to change the JAVA_ home value in the environment variable to the installation path of 1.7, and put JAVA_HOME in front of the Path path. This must be done.

As shown in the figure above, then reopen cmd, enter multiple directories, and enter the command: java-version to see if the switch is successful. If ok, it is successful, otherwise try the latter methods.

2. Find the control panel, select the large icon or small icon for viewing, find the java option and click to enter (Note: this java option is available only after you have installed jre independently).

Then select the java bar, click View, uncheck the enable box of 1.8,9, and save it. Then reopen cmd, go to multiple directories, and enter the command: java-version to see if the switch is successful.

Note: this Java control panel page is available only if jre is installed separately. And only when jre-9 is installed independently will the following interface appear:

The display interface with independent installation of jre1.7 and jre1.8 is not the same as the picture above! As shown in the following figure:

Select the update button to remove the automatic check for updates, do not update automatically. (the following interface is also available only after jre-9 is installed independently)

3. Find the directory C:\ Windows\ System32, and delete java.exe, javaw.exe and javaws.exe.

Then reopen cmd, go to multiple directories, and enter the command: java-version to see if the switch is successful.

4. Find the directory C:\ ProgramData\ Oracle\ Java\ javapath (Note: it is a hidden directory, and you need to open the file extension and hidden project, as shown in the following figure), and delete java.exe, javaw.exe and javaws.exe from the directory.

Note: when we delete all the files in this directory, the environment variable C:\ ProgramData\ Oracle\ Java\ javapath in the Path path will disappear automatically, which is amazing!

Then reopen cmd, go to multiple directories, and enter the command: java-version to see if the switch is successful.

4. If you still can't switch, you can use WIN + R to enter regedit and hit enter to open the registry and find HKEY_LOCAL_MACHINE-- > SOFTWARE-- > JavaSoft.

Click Java Development Kit to change the value of CurrentVersion on the right to the version value you want (right-- > change it).

Then reopen cmd, go to multiple directories, and enter the command: java-version to see if the switch is successful.

Summary

The above is a summary of the switching problems and solutions of installing multiple jdk versions in the win10 64-bit system introduced by the editor. I hope it will be helpful to you. If you have any questions, please leave a message for me, and the editor will reply to you in time!

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