How do i store bytearray as value in hashmaps?

Question

i tried to store a bytearray in a LinkedHashMap

static Map<Long, byte[]> lhm2 = new LinkedHashMap<Long, byte[]>(1000);

But

lhm2.get(1)

will throw a NullPointerException. lhm2 contains key 1 and i checked if it's not null with

if(lhm2.get(1) != null){
    System.out.println("not null");
}

Any suggestions?

Thanks in advance!

Chris

you should use `contansKey(keyName)` to check if a key exists or not — rajesh, Mar 25 '13 at 10:20
Please show a short but *complete* program demonstrating your problem. I strongly suspect it's not where you think it is. That code would only fail if `lhm2` is null. — Jon Skeet, Mar 25 '13 at 10:21
`lhm2.get(1)` can throws NPE only if you try to call a method using this object — Alex Bonel, Mar 25 '13 at 10:24
thanks for your fast support! the comment below fixed my problem, wow — Chris Jung, Mar 25 '13 at 11:21

score 2 · Accepted Answer · answered Mar 25 '13 at 10:58

2

your key should be a long so better do this

lhm2.get(1L)

instead of doing like

lhm2.get(1)

answered Mar 25 '13 at 10:58

Code2Interface

what to do if i want to put it in a for-loop? is a simple cast ok? like lhm2.get((long) i)? – Chris Jung Mar 25 '13 at 11:28
check this link http://stackoverflow.com/questions/1066589/java-iterate-through-hashmap to iterate over your map – Code2Interface Mar 25 '13 at 11:35

score 0 · Answer 2 · answered Mar 25 '13 at 10:22

0

You should do:

if(lhm2.contains(1){
    lhm2.get(1)
}

answered Mar 25 '13 at 10:22

Atropo

2 Answers2