There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                            Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-7-oracle/jre/bin/java          1074      auto mode
  1            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1071      manual mode
* 2            /usr/lib/jvm/java-7-oracle/jre/bin/java          1074      manual mode

Press enter to keep the current choice[*], or type selection number:

$ java -version
java version "1.7.0_45"
Java(TM) SE Runtime Environment (build 1.7.0_45-b18)
Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode)

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update

sudo apt-get install oracle-java8-installer

sudo apt-get install glassfish-javaee

https://www.javatpoint.com/how-to-configure-tomcat-server-in-eclipse-ide

https://www.eclipse.org/downloads/packages/eclipse-ide-java-ee-developers/oxygen3a