Workaround for gradle application plugin 'the input line is too long' error on Windows

build.gradle

tasks.withType(CreateStartScripts).each { task ->
    task.doLast {
        String text = task.windowsScript.text
        text = text.replaceFirst(/(set CLASSPATH=%APP_HOME%\\lib\\).*/, { "${it[1]}*" })
        task.windowsScript.write text
    }
}

Thanks. This helped a lot. I was not having a problem with a classpath that was too long, but I did want everything that was in the /lib directory included on may classpath. Here is what I found worked for both linux and windows.

tasks.withType(CreateStartScripts).each { task ->
    task.doLast {
        task.windowsScript.write task.windowsScript.text.replaceFirst(/(set CLASSPATH=%APP_HOME%\\lib\\).*/, { "${it[1]}*" })
        task.unixScript.write task.unixScript.text.replaceFirst(/(CLASSPATH=.APP_HOME\/lib\/).*/, { "CLASSPATH=\$(echo \$APP_HOME/lib/*.jar | tr ' ' ':')" })
    }
}

Thanks! @barrybecker4: Unfortunately, the line
task.unixScript.write task.unixScript.text.replaceFirst(/(CLASSPATH=.APP_HOME\/lib\/).*/, { "CLASSPATH=\$(echo \$APP_HOME/lib/*.jar | tr ' ' ':')" }) does not work properly when the folder names contain a space character in Unix. Instead, the same idea as for Windows may be used:
task.unixScript.write task.unixScript.text.replaceFirst(/(CLASSPATH=.APP_HOME\/lib\/).*/, { "${it[1]}*" })

Helpful workaround. A slightly cleaner approach in the same vein is to override the classpath property in the startScripts, which is the pre-configured task of type CreateStartScripts added by the "application" plugin.

startScripts {
    classpath = files( '$APP_HOME/lib/*' )
}