Eclipse won't open in Linux Mint and Java won't open in different directories

Question

I had Installed Eclipse in /opt/eclipse in Linux Mint 18.2 cinnamon with openjdk-9 (please don't tell me switch over oracle jdk). Whenever I click on Eclipse icon this window shows up:

Here is the content of that window:

JVM terminated. Exit code=1
/usr/bin/java
-Dosgi.requiredJavaVersion=1.8
[email protected]/eclipse-workspace
-XX:+UseG1GC
-XX:+UseStringDeduplication
--add-modules=ALL-SYSTEM
-Dosgi.requiredJavaVersion=1.8
-Xms256m
-Xmx1024m
--add-modules=ALL-SYSTEM
-jar /opt/eclipse//plugins/org.eclipse.equinox.launcher_1.4.0.v20161219-1356.jar
-os linux
-ws gtk
-arch x86_64
-showsplash /opt/eclipse//plugins/org.eclipse.epp.package.common_4.7.1.20171005-1200/splash.bmp
-launcher /opt/eclipse/eclipse
-name Eclipse
--launcher.library /opt/eclipse//plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.550.v20170928-1359/eclipse_1629.so
-startup /opt/eclipse//plugins/org.eclipse.equinox.launcher_1.4.0.v20161219-1356.jar
--launcher.appendVmargs
-exitdata 828016
-product org.eclipse.epp.package.java.product
-vm /usr/bin/java
-vmargs
-Dosgi.requiredJavaVersion=1.8
[email protected]/eclipse-workspace
-XX:+UseG1GC
-XX:+UseStringDeduplication
--add-modules=ALL-SYSTEM
-Dosgi.requiredJavaVersion=1.8
-Xms256m
-Xmx1024m
--add-modules=ALL-SYSTEM
-jar /opt/eclipse//plugins/org.eclipse.equinox.launcher_1.4.0.v20161219-1356.jar 

Here is my Java:

$java -version
openjdk version "9-internal"
OpenJDK Runtime Environment (build 9-internal+0-2016-04-14-195246.buildd.src)
OpenJDK 64-Bit Server VM (build 9-internal+0-2016-04-14-195246.buildd.src, mixed mode)

Also when I type the same command in /opt/eclipse I get this:

/opt/eclipse $ java -version
Error occurred during initialization of VM
java.lang.Error: Properties init: Could not determine current working directory.
    at java.lang.System.initProperties(java.base/Native Method)
    at java.lang.System.initPhase1(java.base/System.java:1850)

when I try to open it from terminal I get this:-

$ eclipse 
Unrecognized option: --add-modules=ALL-SYSTEM
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.

Answer 1

In the file eclipse.ini remove the line --add-modules=ALL-SYSTEM.

In Java 9 the Java Platform Module System was introduced which encapsulate most internal APIs. The --add-modules=ALL-SYSTEM is a Java 9 virtual machine (VM) argument to make it behave like before Java 9.

See JEP 261: Module System:

As a further special case at run time, if is ALL-SYSTEM then all system modules are added to the root set, whether or not they are in the default set. This is sometimes needed by test harnesses. This option will cause many modules to be resolved; in general, ALL-DEFAULT should be preferred.