JOSM tries to use Java 6 when installed

[shoorick]

JOSM stops when Java 6 installed even Java 7 presented too. Checked under Ubuntu 12.04 LTS with simultaneously installed Java 6 and 7. JOSM which spawned from terminal produce error:

Using /usr/lib/jvm/java-6-openjdk-i386/bin/java to execute josm.
Exception in thread "main" java.lang.UnsupportedClassVersionError: JOSM : Unsupported major.minor version 51.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:643)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:323)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:268)
Could not find the main class: JOSM. Program will exit.

How to resolve

Remove paths to Java 6 from /usr/bin/josm:

josm

@@ -11 +11 @@
 
 # If OpenJDK is only available headless, do not try it
 if dpkg --get-selections 'openjdk-*-jre' | grep install$ > /dev/null ; then
-        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-openjdk/bin/java /usr/lib/jvm/java-7-openjdk-$ARCH/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/lib/jvm/java-6-openjdk/bin/java /usr/lib/jvm/java-6-openjdk-$ARCH/bin/java /usr/lib/jvm/java-6-sun/bin/java"
+        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-openjdk/bin/java /usr/lib/jvm/java-7-openjdk-$ARCH/bin/java /usr/lib/jvm/java-7-oracle/bin/java"
 else
-        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/lib/jvm/java-6-sun/bin/java /usr/bin/java"
+        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/bin/java"
 fi
 
 JAVA_OPTS="-Djosm.restart=true -Djava.net.useSystemProxies=true $JAVA_OPTS"

[skyper]

See also #8700.

[bastiK]

The following changes have been applied (for next release):

tested/usr/bin/josm

@@ -11 +11 @@
 
 # If OpenJDK is only available headless, do not try it
 if dpkg --get-selections 'openjdk-*-jre' | grep install$ > /dev/null ; then
-        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-openjdk/bin/java /usr/lib/jvm/java-7-openjdk-$ARCH/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/lib/jvm/java-6-openjdk/bin/java /usr/lib/jvm/java-6-openjdk-$ARCH/bin/java /usr/lib/jvm/java-6-sun/bin/java"
+        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-openjdk/bin/java /usr/lib/jvm/java-7-openjdk-$ARCH/bin/java /usr/lib/jvm/java-7-oracle/bin/java"
 else
-        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/lib/jvm/java-6-sun/bin/java /usr/bin/java"
+        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/bin/java"
 fi
 
 JAVA_OPTS="-Djosm.restart=true -Djava.net.useSystemProxies=true $JAVA_OPTS"

latest/usr/bin/josm-latest

@@ -11 +11 @@
 
 # If OpenJDK is only available headless, do not try it
 if dpkg --get-selections 'openjdk-*-jre' | grep install$ > /dev/null ; then
-        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-openjdk/bin/java /usr/lib/jvm/java-7-openjdk-$ARCH/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/lib/jvm/java-6-openjdk/bin/java /usr/lib/jvm/java-6-openjdk-$ARCH/bin/java /usr/lib/jvm/java-6-sun/bin/java"
+        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-openjdk/bin/java /usr/lib/jvm/java-7-openjdk-$ARCH/bin/java /usr/lib/jvm/java-7-oracle/bin/java"
 else
-        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/lib/jvm/java-6-sun/bin/java /usr/bin/java"
+        JAVA_CMDS="$JAVA_HOME/bin/java /usr/lib/jvm/java-7-oracle/bin/java /usr/bin/java"
 fi
 
 JAVA_OPTS="-Djosm.restart=true -Djosm.home=$HOME/.josm-latest -Djava.net.useSystemProxies=true $JAVA_OPTS"

[skyper]

The dependencies of the package also need to be adjusted to make sure that openjdk-7 is installed.

[Don-vip]

I have applied the following changes, for next release:

latest/DEBIAN/control

@@ -2 +2 @@
 Version: 1.5.svn{{VERSION}}
 Section: utils
 Maintainer: josm developers <josm-dev@openstreetmap.org>
-Homepage: http://josm.openstreetmap.de
+Homepage: https://josm.openstreetmap.de
 Priority: extra
 Architecture: all
-Depends: openjdk-6-jre | sun-java6-jre | openjdk-7-jre
+Depends: openjdk-7-jre
 Description: Editor for OpenStreetMap (daily development snapshot)
  JOSM is an editor for OpenStreetMap (OSM) written in Java.
   The current version supports stand alone GPX tracks, GPX track data

latest/usr/bin/josm-latest

@@ -2 +2 @@
 # Simple wrapper script used to start JOSM in Debian
 set -e
 
-# First, the alternative (if known to work) or users preference as defined by $JAVA_HOME. Next, use OpenJDK or Sun's proprietary JDK.
+# First, the alternative (if known to work) or users preference as defined by $JAVA_HOME. Next, use OpenJDK or Oracle's proprietary JDK.
 # Override to a specific one using $JAVACMD
 ALTERNATIVE_JDK="`readlink -n -f /etc/alternatives/java`"
 

tested/usr/bin/josm

@@ -2 +2 @@
 # Simple wrapper script used to start JOSM in Debian
 set -e
 
-# First, the alternative (if known to work) or users preference as defined by $JAVA_HOME. Next, use OpenJDK or Sun's proprietary JDK.
+# First, the alternative (if known to work) or users preference as defined by $JAVA_HOME. Next, use OpenJDK or Oracle's proprietary JDK.
 # Override to a specific one using $JAVACMD
 ALTERNATIVE_JDK="`readlink -n -f /etc/alternatives/java`"
 

tested/DEBIAN/control

@@ -2 +2 @@
 Version: 1.5.svn{{VERSION}}
 Section: utils
 Maintainer: josm developers <josm-dev@openstreetmap.org>
-Homepage: http://josm.openstreetmap.de
+Homepage: https://josm.openstreetmap.de
 Priority: extra
 Architecture: all
-Depends: openjdk-6-jre | sun-java6-jre | openjdk-7-jre
+Depends: openjdk-7-jre
 Conflicts: josm-plugins
 Replaces: josm-plugins
 Description: Editor for OpenStreetMap