Configure default system JDK

scripts/install_java.bat

@@ -1,3 +1,9 @@
+:: This script will download and install the appropriate JDK for use with Bisq development.
+:: It will also configure it as the default system JDK.
+:: If you need to change to another default JDK for another purpose later, you just need to
+:: change the JAVA_HOME environment variable. For example, use the following command:
+::     setx /M JAVA_HOME "<JDK_PATH>"
+
 @echo off
 
 :: Ensure we have administrative privileges in order to install files and set environment variables

scripts/install_java.sh

@@ -1,4 +1,10 @@
 #!/usr/bin/env bash
+# This script will download and install the appropriate JDK for use with Bisq development.
+# It will also configure it as the default system JDK.
+# If you need to change to another default JDK for another purpose later, you can use the
+# following commands and select the default JDK:
+#     update-alternatives --config java
+#     update-alternatives --config javac
 
 JAVA_HOME=/usr/lib/jvm/openjdk-10.0.2
 JDK_FILENAME=openjdk-10.0.2_linux-x64_bin.tar.gz
@@ -31,3 +37,6 @@ if [ ! -d "$JAVA_HOME" ]; then
     update-alternatives --install /usr/bin/java java $JAVA_HOME/bin/java 2000
     update-alternatives --install /usr/bin/javac javac $JAVA_HOME/bin/javac 2000
 fi
+
+update-alternatives --set java $JAVA_HOME/bin/java
+update-alternatives --set javac $JAVA_HOME/bin/javac