Java error on debrief

Hi Team,

Please advice the cause of getting the below error facing while doing the Material install debrief, as soon as I hit on the 'Add items' option for install debrief system throws this error. I have attached the exception details for your reference.

I remember when first time this error came I realised the reason might be that parts in 'available' quantity is zero because when got the parts in available quantity then this error didn't come and I added the items easily as per the sub options available under the 'Add items'.

However today having the items in available and yesterday also tried with available items, this error kept on coming and still I am facing this JAVA exception error.