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The EV3 brick has a similar feature. However it does not require any code changes. Just run the ev3console program in the bin directory of your leJOS installation from command line. The output of the brick will be printed to this command line.

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Problem Solving

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The following presents typical issues and how to solve them.
Issue Typical Error Messages Description Solution
leJOS EV3 does not support Java 8
"java.lang.UnsupportedClassVersionError"
"unsupported major.minor version"
You compile the sources in your project with Java 8 and upload them to the brick. However the lejos EV3 does not support Java 8 Go to the project properties and switch to Java 7 (Right Click on project > Properties > Java Compiler > Compiler compliance level)
Uploading to the brick does not respondTODO not the only reason

You compile a file successfully and when uploading the result, the connected brick is found. Anyway the upload does not terminate and does not react. Flash the brick with the current leJOS firmware. If the brick is recognized correctly and the attempt to upload a compiled file fails then the firmware on the brick might be outdated. If connecting via bluetooth works add -b to the uxjupload/nxj command.
Compilation and uploading works from command line but not when using KIELER
This Java instance does not support a 32-bit JVM. Please install the desired version.
You can compile and upload code to the brick using the command line tools but when using KIELER an error message apprears because Java does not support 32-bit JVM. Set the LEJOS_NXT_JAVA_HOME environment variable, such that it points to an 32-bit JDK and is visible for GUI applications (or at least KIELER). The process to do so differs on every OS. As alternative, execute KIELER from terminal.
Brick does nothing after program finished and prints "Program exit"
A program was uploaded and finished without errors. Afterwards the brick prints "Program exit" but does not open the main menu.
This is normal behaviour if uploading a program in debug mode instead run mode (Debug As instead Run As in Eclipse). To get back to the main menu, press the ENTER and ESCAPE button of the brick at the same time.
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Old Version 14

New Version 15

Key

Problem Solving

Issue	Typical Error Messages	Description	Solution
leJOS EV3 does not support Java 8	"java.lang.UnsupportedClassVersionError" "unsupported major.minor version"	You compile the sources in your project with Java 8 and upload them to the brick. However the lejos EV3 does not support Java 8	Go to the project properties and switch to Java 7 (Right Click on project > Properties > Java Compiler > Compiler compliance level)
Uploading to the brick does not respondTODO not the only reason		You compile a file successfully and when uploading the result, the connected brick is found. Anyway the upload does not terminate and does not react.	Flash the brick with the current leJOS firmware. If the brick is recognized correctly and the attempt to upload a compiled file fails then the firmware on the brick might be outdated. If connecting via bluetooth works add -b to the uxjupload/nxj command.
Compilation and uploading works from command line but not when using KIELER	This Java instance does not support a 32-bit JVM. Please install the desired version.	You can compile and upload code to the brick using the command line tools but when using KIELER an error message apprears because Java does not support 32-bit JVM.	Set the LEJOS_NXT_JAVA_HOME environment variable, such that it points to an 32-bit JDK and is visible for GUI applications (or at least KIELER). The process to do so differs on every OS. As alternative, execute KIELER from terminal.
Brick does nothing after program finished and prints "Program exit"		A program was uploaded and finished without errors. Afterwards the brick prints "Program exit" but does not open the main menu.	This is normal behaviour if uploading a program in debug mode instead run mode (Debug As instead Run As in Eclipse). To get back to the main menu, press the ENTER and ESCAPE button of the brick at the same time.