What causes "Unable to access jarfile" error?

Question

I had encountered this issue when I had run my Jar file as

java -jar TestJar

instead of

java -jar TestJar.jar

Missing the extension .jar also causes this issue.

Fixed

I just placed it in a different folder and it worked.

[Possibly Windows only]

Beware of spaces in the path, even when your jar is in the current working directory. For example, for me this was failing:

java -jar myjar.jar

I was able to fix this by givng the full, quoted path to the jar:

java -jar "%~dp0\myjar.jar" 

Credit goes to this answer for setting me on the right path....

I had this issue under CygWin in Windows. I have read elsewhere that Java does not understand the CygWin paths (/cygdrive/c/some/dir instead of C:\some\dir) - so I used a relative path instead: ../../some/dir/sbt-launch.jar.

I had the same issue when trying to launch the jar file. The path contained a space, so I had to place quotes around. Instead of:

java -jar C:\Path to File\myJar.jar

i had to write

java -jar "C:\Path to File\myJar.jar"

Just came across the same problem trying to make a bad USB...

I tried to run this command in admin cmd

java -jar c:\fw\ducky\duckencode.jar -I c:\fw\ducky\HelloWorld.txt  -o c:\fw\ducky\inject.bin

But got this error:

Error: unable to access jarfile c:\fw\ducky\duckencode.jar

Solution

1st step

Right click the jarfile in question. Click properties. Click the unblock tab in bottom right corner. The file was blocked, because it was downloaded and not created on my PC.

2nd step

In the cmd I changed the directory to where the jar file is located.

cd C:\fw\ducky\

Then I typed dir and saw the file was named duckencode.jar.jar

So in cmd I changed the original command to reference the file with .jar.jar

java -jar c:\fw\ducky\duckencode.jar.jar -I c:\fw\ducky\HelloWorld.txt  -o c:\fw\ducky\inject.bin

That command executed without error messages and the inject.bin I was trying to create was now located in the directory.

Hope this helps.

I had a similar problem and I even tried running my CMD with administrator rights, but it did not solve the problem.

The basic thing is to make sure to change the Directory in cmd to the current directory where your jar file is.

Do the following steps:

1. Copy jar file to Desktop.

2. Run CMD

3. Type command cd desktop

4. Then type java -jar filename.jar

This should work.

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Edit: From JDK-11 onwards ( JEP 330: Launch Single-File Source-Code Programs )

Since Java 11, java command line tool has been able to run a single-file source-code directly. e.g.

java filename.java