Update your system's java alternatives and choose JDK 10:
$ sudo update-alternatives --config java
here are 3 choices for the alternative java (providing /usr/bin/java).
Selection Path Priority Status
------------------------------------------------------------
0 /usr/lib/jvm/java-9-openjdk-amd64/bin/java 1091 auto mode
* 1 /usr/lib/jvm/java-10-openjdk-amd64/bin/java 1 manual mode
2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 manual mode
3 /usr/lib/jvm/java-9-openjdk-amd64/bin/java 1091 manual mode
Press <enter> to keep the current choice[*], or type selection number:
还有
$ sudo update-alternatives --config javac
There are 3 choices for the alternative javac (providing /usr/bin/javac).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-9-openjdk-amd64/bin/javac 1091 auto mode
1 /usr/lib/jvm/java-10-openjdk-amd64/bin/javac 1 manual mode
2 /usr/lib/jvm/java-8-openjdk-amd64/bin/javac 1081 manual mode
3 /usr/lib/jvm/java-9-openjdk-amd64/bin/javac 1091 manual mode
Press <enter> to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/lib/jvm/java-10-openjdk-amd64/bin/javac to provide /usr/bin/javac (javac) in manual mode