CODEWITHSUNDEEP
javahashtable
David Solé González
David Solé González

Reputation: 120

Check if Hashtable.get worked

I'm working with on a Java program that checks a config file integrity.

On some point, I need to ensure that some mandatory values are setted up, either give it a default value.

So, I made a HashTable<String, String> working like a key => value table. On this table I store all the configuration lines on the file, and then I check it.

The problem comes when a specific value does not exist, for example:

String p = null;
/*...*/

//here I'm trying to get the LOG value
p = this.PAIRS.get("LOG");

if(p.equals(null) || p.equals("")){
    //set default value
}

The problem is that I'm getting a NullPointerException, so it would be fine if someone can help me on how to determinate if this.PAIRS.get("LOG"); found a key or not...

Thanks!

EDIT: Solved, the right thing was using == and not an equals.

Thanks again!

Upvotes: 0

Views: 69

Answers (2)

gati sahu
gati sahu

Reputation: 2626

p = this.PAIRS.get("LOG");

This code return null if the key is not present and when you are doing below statement it will throw exception

if(p.equals(null) || p.equals("")){
    //set default value
}

Instead check null first then do .equals

 if(p==null || p.equals("")){
        //set default value
    }

Upvotes: 0

jvwilge
jvwilge

Reputation: 2534

If p is null, a NullPointerException will be thrown because it is not an instance of an Object (so the equals method doesn't exist). Checking for null should be done the following way : p == null

Upvotes: 2

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