Create classic applet project. Add one line to process() method:

    public void process(APDU apdu) {
        ISOException.throwIt((short) (0x9001));
    }

Run it. Right click on project entry and select "unload". Console output:

init-platform-properties:
Using JavaCard Platform Definition at C:\Users\<user>\.netbeans\dev\config\Services\Platforms\org-netbeans-api-java-Platform\javacard_default.jcplatform
Java Card Home is <dir> (Java Card Platform)
init-ri-properties:
init-device-properties:
Platform device property name is jcplatform.javacard_default.devicespath
Computed device folder path is C:\Users\<user>\.netbeans\dev\config\org-netbeans-modules-javacard\servers\javacard_default
Platform device file path property name is C:\Users\<user>\.netbeans\dev\config\org-netbeans-modules-javacard\servers\javacard_default\Default Device.jcard
Deploying to device Default Device http port 8019
init-keystore:
Keystore is <dir>/samples/keystore/a.keystore
unload-bundle:
unload-dependencies:
BUILD SUCCESSFUL (total time: 0 seconds)

So, installer wasn't invoked. Right click on APDU script and select "Send To Card", output is:

CLA: 00, INS: a4, P1: 04, P2: 00, Lc: 06, 64, 3f, 53, ce, 15, 45, Le: 00, SW1: 90, SW2: 01

So, applet still can be selected. "Unload" doesn't work.

Build used is #52.