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Heroku unable to detect java 11

I am trying to deploy a java jar to heroku with heroku maven plugin.
I am using java 11 so I have added system.properties in the root folder(where pom.xml is present) and set java.runtime.version=11. However it doesn't seem to be working !
My plugin :
<plugin>
<groupId>com.heroku.sdk</groupId>
<artifactId>heroku-maven-plugin</artifactId>
<version>3.0.1</version>
<configuration>
<includeTarget>false</includeTarget>
<includes>
<include>${project.build.directory}/${project.build.finalName}.jar</include>
</includes>
<processTypes>
<web>java $JAVA_OPTS -jar ${project.build.directory}/${project.build.finalName}.jar</web>
</processTypes>
</configuration>
</plugin>
When I do git push heroku master it starts build process using jdk 8.
remote: Building source:
remote:
remote: -----> Java app detected
remote: -----> Installing JDK 1.8... done
remote: -----> Installing Maven 3.6.2... done
remote: -----> Executing Maven
remote: $ mvn -DskipTests clean dependency:list install
Eventually build fails with error :
Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project ImpactHub_bot: Fatal error compiling: invalid flag: --release ->
How do I set jdk verison to 11 ? I have also tried adding ${java.version} to configuration but it didn't help

That's exactly how you are specifying the Java version, see: https://devcenter.heroku.com/articles/java-support#specifying-a-java-version
You can specify a Java version by adding a file called
system.properties to your application.
Set a property java.runtime.version in the file:
java.runtime.version=11
I used it in my project as well and it is working.
Make sure your system.properties is saved as All Files. Furthermore it should be at the root folder of your git repo.
It might have a .txt ending. If that fails open a Support Ticket with Heroku.

Compilation error Multiple version of JAVA

I am having the below issue when I run my maven build in eclipse. I saw many posts like this but i still can't solve this problem .Mine may be a little more specific, I know that my JAVA_HOME is pointed to java6, and that is because I am working on another application which uses java 6. The application in which I am running into issues uses Java 8
[ERROR] COMPILATION ERROR : [INFO] -------------------------------------------------------------
[ERROR] Unable to locate the Javac Compiler in: C:\Program Files\Java\jre1.8.0_92\..\lib\tools.jar Please ensure you are using JDK 1.4 or above and not a JRE (the com.sun.tools.javac.Main class is required). .In most cases you can change the location of your Java installation by setting the JAVA_HOME environment variable. [INFO] 1 error
<br>[INFO] -------------------------------------------------------------
<br>[INFO] ------------------------------------------------------------------------
<br>[INFO] BUILD FAILURE [INFO] ------------------------------------------------------------------------
<br>[INFO] Total time: 11:53 min [INFO] Finished at: 2016-08-18T16:52:13+05:30
<br>[INFO] Final Memory: 11M/141M
<br>[INFO] ------------------------------------------------------------------------
<br>[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project
Compilation failure [ERROR] Unable to locate the Javac Compiler in: [ERROR] C:\Program Files\Java\jre1.8.0_92\..\lib\tools.jar
[ERROR] Please ensure you are using JDK 1.4 or above and [ERROR] not a JRE (the com.sun.tools.javac.Main class is required).
<br>[ERROR] In most cases you can change the location of your Java [ERROR] installation by setting the JAVA_HOME environment variable.
[ERROR] -> [Help 1] org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile
How can I resolve this problem without installing java 8 as it may may make changes to my JAVA_HOME etc which would make my other application to not run. Is there a way to get the JDK folder without running the .exe (p.s I already tried the 7zip method)
Please suggest

If you have the jdk8 then you can open cmd, run the command in this window to modify the JAVA_HOME set JAVA_HOME=<jdk8 path>. This will modify the JAVA_HOME env variable only for this instance of the cmd session and not for the whole OS. Now run the maven build command from this window and it wont fail.
If you wanna run the build from eclipse, then in eclipse try going to Windows --> Preferences --> Java --> Installed JREs --> click Add button --> Sel Standard VM and click next --> put in values for 'JRE Home' as path till the jdk folder and 'JRE Name' as java8 or whatever you wish --> click Finish.
Now right click the project of you interest --> click properties --> Java Compiler --> Tick 'Enable project specific settings' --> and select 1.8 here.
If 1.8 is not visible here, go to Java Build Path --> Add Library --> JRE System Library --> Alternate JRE --> select jdk8 --> Finish

Looking at the path in that error (C:\Program Files\Java\jre1.8.0_92\..\lib\tools.jar) you've installed the Java Runtime Environment (JRE).
To compile java you need the Java Development Kit (JDK) which contains the tools the maven plugin needs.

You can change your maven-compiler-plugin configurations to your JAVA_HOME.
Just go to eclipse window->preferences->type maven->and you could see something like template click on that and look for javac compiler, just go there and change to whatever java version you have.
<configuration>
<!-- http://maven.apache.org/plugins/maven-compiler-plugin/ -->
<source>${cursor}1.6</source>
<target>1.6</target>
</configuration>
Without java8 and without .exe file you can't go ahead with your requirement.
Hope it's useful.

from your error log it says that
[ERROR] Unable to locate the Javac Compiler in: [ERROR] C:\Program Files\Java\jre1.8.0_92\..\lib\tools.jar
paste this code in your pom.xml inside build tag and make sure you add dependencies properly and please change your java version accordingly
this will only work if you have something wrong in your pom.xml.
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<verbose>true</verbose>
<fork>true</fork>
<executable>${JAVA_HOME}/bin/javac</executable>
<compilerVersion>1.8</compilerVersion>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.4.2</version>
<configuration>
<jvm>${JAVA_HOME}/bin/java</jvm>
<forkMode>once</forkMode>
</configuration>
</plugin>
</plugins>
note your JAVA_HOME must point like this
C:\Program Files\Java\jdk1.8.0_65
edit
There must be various reasons like
your pom is not getting path to java home
your java home is not set
you are using jre instead of jdk in your IDE

You can download the version of the JDK without installer.
Then specify a JDK 1.8 as source and target in the compiler configuration of the pom.xml with which you have your problem. in this way you don't need changing your JAVA_HOME :
<build>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
<compilerVersion>1.8</compilerVersion>
<fork>true</fork>
<executable>D:\jdk1.8\bin\javac</executable>
</configuration>
</plugin>
<build>

I followed steps in the below link to get the portable JDK:
http://bgasparotto.com/convert-jdk-exe-zip/

exec-maven-plugin says cannot run specified program, even though it is on the PATH

Edit 20140716:
Solution found
tl;dr = exec-maven-plugin does not recognise .cmd files, but only .bat files, as executable scripts. Rename grunt.cmd --> grunt.bat, bower.cmd --> bower.bat, etc. as a workaround.
Having done npm install -g grunt-cli on my system, grunt is most certainly on the PATH
When I run maven install however, this doesn't seem to register.
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:exec
(build-spa-bower) on project foobar: Command execution failed.
Cannot run program "grunt" (in directory "C:\workspace\foobar\src\main\spa"):
CreateProcess error=2, The system cannot find the file specified -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException:
Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:exec
(build-spa-bower) on project foobar: Command execution failed.
Just to be sure, in the same terminal, I have executed this
cd C:\workspace\foobar\src\main\spa
grunt build
... in the same terminal as I issued the maven command above, and grunt executes just fine.
Does exec-maven-plugin use the PATH environment variable, or does it need to be told that this executable exisst in some other way?
EDIT:
This documentation suggests that executables on PATH should be found, so it stumps me further.

I dug into the source code of exec-maven-plugin and found this snippet.
From the source of ExecMojo#getExecutablePath:
CommandLine toRet;
if ( OS.isFamilyWindows() && exec.toLowerCase( Locale.getDefault() ).endsWith( ".bat" ) )
{
toRet = new CommandLine( "cmd" );
toRet.addArgument( "/c" );
toRet.addArgument( exec );
}
else
{
toRet = new CommandLine( exec );
}
I compared this to another plugin that ran grunt tasks from maven, and found this
if (isWindows()) {
command = "cmd /c " + command;
}
... and that worked for me. So essentially the latter worked because all commands in WIndows were prepended with cmd /c,
whereas the exec-maven-plugin did not, because it only did so for file ending in .bat.
Looking in C:\Users\USER\AppData\Roaming\npm, I see:
node_modules (folder)
grunt (unix script file)
grunt.cmd (windows script file)
When I rename grunt.cmd --> grunt.bat, this solves the problem, and exec-maven-plugin is able to run this command.
(this also applies to other executables created using npm install -g, such as bower and yo)

In addition to bguiz' answer, which would be the best solution, I've created a workaround using Maven profiles, bypassing the problem.
This is a temporary solution, until the maven-exec-plugin's bug gets fixed.
Please upvote the bug report here: http://jira.codehaus.org/browse/MEXEC-118
Edit: The bug is resolved, you can point to 1.4-SNAPSHOT to fix it.
<project>
(...)
<profiles>
<profile>
<id>grunt-exec-windows</id>
<activation>
<os>
<family>Windows</family>
</os>
</activation>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>${exec-maven-plugin.version}</version>
<executions>
<execution>
<id>grunt-default</id>
<phase>generate-resources</phase>
<configuration>
<executable>cmd</executable>
<arguments>
<argument>/C</argument>
<argument>grunt</argument>
</arguments>
</configuration>
<goals>
<goal>exec</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>
</project>

I had the same issue with 1.5.0 of the plugin.
The cause in my case was spaces in my user name resulting in a grunt path:
C:\Users\My name with spaces\AppData\Roaming\npm.
When I moved the contents of the npm directory to a path without spaces, it worked.

Is it possible to get maven to accept maxerrs for its compiler plugin?

I have a project where I am responsible for fixing some errors and another developer is responsible for other errors. The number of errors is well over a hundred, and as I'm fixing my errors, her errors are piling up. I'm at the point where I see 99 of her errors and one of mine, and I assume I will soon get to a point where it is 100 of hers. I looked into using this configuration for maven:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<compilerArgument>-Xmaxerrs 1000</compilerArgument>
</configuration>
</plugin>
But no dice:
Failure executing javac, but could not parse the error:
javac: invalid flag: -Xmaxerrs 1000
Usage: javac <options> <source files>
use -help for a list of possible options
On the command line using javac, the maxerrs flag works as expected, but I can't seem to make the leap to maven with it.
Any ideas?

Using the "Map syntax" worked for me:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.1</version>
<configuration>
<fork>true</fork>
<compilerArguments>
<Xmaxerrs>1000</Xmaxerrs>
</compilerArguments>
</configuration>
</plugin>
The option is passed as expected:
$ mvn clean compile -X
...
[DEBUG] Using compiler 'javac'.
[DEBUG] Source directories: [/home/pascal/Projects/stackoverflow/Q3358242/src/main/java]
[DEBUG] Classpath: [/home/pascal/Projects/stackoverflow/Q3358242/target/classes]
[DEBUG] Output directory: /home/pascal/Projects/stackoverflow/Q3358242/target/classes
[DEBUG] Classpath:
[DEBUG] /home/pascal/Projects/stackoverflow/Q3358242/target/classes
[DEBUG] Source roots:
[DEBUG] /home/pascal/Projects/stackoverflow/Q3358242/src/main/java
[DEBUG] Command line options:
[DEBUG] -d /home/pascal/Projects/stackoverflow/Q3358242/target/classes -classpath /home/pascal/Projects/stackoverflow/Q3358242/target/classes: -sourcepath /home/pascal/Projects/stackoverflow/Q3358242/src/main/java: /home/pascal/Projects/stackoverflow/Q3358242/src/main/java/com/stackoverflow/q3358242/App.java -g -nowarn -target 1.5 -source 1.5 -encoding UTF-8 -Xmaxerrs 1000
[INFO] Compiling 1 source file to /home/pascal/Projects/stackoverflow/Q3358242/target/classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
...
The odd part is that I get the exact same debug output (with the exact same Command line options) when using the alternative configuration you provided... except that it fails due to a Failure executing javac. You should raise a Jira issue, there is definitely something weird.

Updating answer for 2022. This works for me with maven-compiler-plugin version 3.8.1:
<configuration>
<source>${compiler.source}</source>
<target>${compiler.target}</target>
<showWarnings>true</showWarnings>
<compilerArgs>
<arg>-Xmaxerrs</arg>
<arg>10000</arg>
</compilerArgs>
</configuration>

Maven GAE Plugin - Unable to run gae:debug

I'm having trouble running the gae:debug goal of the Maven GAE Plugin. The error I'm receiving is below. Any ideas?
I'm running it with "mvn gae:debug".
[INFO] Packaging webapp
[INFO] Assembling webapp[test-gae] in [C:\development\test-gae\target\test-gae-0.0.1-SNAPSHOT]
[INFO] Processing war project
[INFO] Webapp assembled in[56 msecs]
[INFO] Building war: C:\development\test-gae\target\test-gae-0.0.1-SNAPSHOT.war
[INFO] [statemgmt:end-fork]
[INFO] Ending forked execution [fork id: -2101914270]
[INFO] [gae:debug]
Usage: <dev-appserver> [options] <war directory>
Options:
--help, -h Show this help message and exit.
--server=SERVER The server to use to determine the latest
-s SERVER SDK version.
--address=ADDRESS The address of the interface on the local machine
-a ADDRESS to bind to (or 0.0.0.0 for all interfaces).
--port=PORT The port number to bind to on the local machine.
-p PORT
--sdk_root=root Overrides where the SDK is located.
--disable_update_check Disable the check for newer SDK versions.
EDIT: gae:run with the jvmFlags option is also giving me the same result with the below configuration.
<plugin>
<groupId>net.kindleit</groupId>
<artifactId>maven-gae-plugin</artifactId>
<version>0.5.0</version>
<configuration>
<jvmFlags>
<jvmFlag>-Xdebug</jvmFlag>
<jvmFlag>-Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000</jvmFlag>
</jvmFlags>
</configuration>
</plugin>

It looks like this is an open issue. I have submitted a patch for this (see Issue 38).