Crazy Mistakes in Force.com Development I - System.StringException: Invalid id

I have faced so many issues when I’m doing the development and could able to resolve almost all of them with the help of force.com developer forum and SFSE. When I’m thinking of the time I had to spend for them and the difficulties I have faced, I thought to share those problems as well as the appropriate solutions that I could made. Because I believe it may save some other developer’s time.

I’ll keep updating this post series time to time when I catch more other birds.

Prob: System.StringException: Invalid id tempStr

Possibilities:

1). Mostly this will happen when trying to assign query parameters into variables like below

Id accId = ApexPages.currentPage().getParameter('accId');

view raw Id_error.txt hosted with ❤ by GitHub

If the value that has passed for accId is not in correct Id format, this exception will be thrown and hard to find out. It's better to assign the value to a variable type of String

String strAccId = ApexPageentPage().getParameters().get('accId');

view raw str_fix hosted with ❤ by GitHub

or use try catch to validate properly

	try{
	Id accId = ApexPages.currentPage().getParameters().get('accId');
	}catch(System.StringException ex){
	// notify user about malformed Id
	}

view raw validate_Id hosted with ❤ by GitHub

2). Also if you try to compare a variable type of Id with a String there's a chance of throwing this since the applied String is not in the standard Id format

	List<Account> acntList = [SELECT Id, Name FROM Account LIMIT 5];
	String a = 'someString';
	if( a != accntList[0].Id){ // this is trying to compare an Id with a malformed string
	System.debug('Oops!');
	}

view raw err_Id_compare hosted with ❤ by GitHub

To overcome this issue it can be used the string value of the Id to compare. 

	if(a != String.valueOf(accntList[0].Id)){
	System.debug(Now fine!');
	}

view raw fix_compare_Id hosted with ❤ by GitHub