java environment variable does not take effect

Today, I found a colleague to change jdk8. After configuring the environment variables, it will not take effect. Later, I found that someone had installed the jdk7 version on this computer before, which is the installed version. Therefore, there are java, javac and other commands under the system32 folder. Variables will use system32 directly, instead of using the configured ones, delete the ones below system32 to take effect