Java stream filter null pointer issue

Question

I have the following stream:

services = services.stream()
        .filter(service -> (service.getType().isEmpty() || service.getType().equals(type)))
        .collect(Collectors.toList());

where service.type is string, and type is also a string. My filter should return all services with its type equal to null (or simply blank), or the given type.

This throws me an error of:

java.lang.NullPointerException: null at com.eternity.service.OrderService.lambda$getServicesForOrder$0(OrderService.java:140) ~[classes/:na] at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174) ~[na:1.8.0_77] at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1374) ~[na:1.8.0_77] at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_77] at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_77] at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_77] at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_77] at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_77] at com.eternity.service.OrderService.getServicesForOrder(OrderService.java:141) ~[classes/:na]

What am I missing?

Did you try to debug ? Never tried on a lambda expression to be fair. — AxelH
– AxelH, Commented Sep 23, 2016 at 6:56

Blake · Accepted Answer · 2018-03-16 13:00:40Z

8

The issue was: I was using .isEmpty() on a null object. I had to use StringUtils.isEmpty() method:

services = services.stream()
        .filter(service -> (StringUtils.isEmpty(service.getType()) || service.getType().equals(type)))
        .collect(Collectors.toList());

edited Mar 16, 2018 at 13:00

Blake

2,1272 gold badges12 silver badges11 bronze badges

answered Sep 23, 2016 at 6:59

uksz

18.4k31 gold badges102 silver badges172 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Mark Brown Over a year ago

You could have also pre-filtered out the null objects with .filter(Objects::nonNull)

kkpareek Over a year ago

In case the whole object is not null, the attribute you are trying to access might be null. As here service.getType could give a null value. Can be filtered with .filter(service -> service.getType() != null)

Sayan Bhattacharya · Accepted Answer · 2022-06-24 16:17:16Z

0

Too late for an answer but still posting this here if anyone comes across this post. Try to use filter out all the objects which are null or have some property that can be null, before performing any operations on the same.
In this case

list.stream()
    //.filter(Objects::nonNull) // use when the whole object can be null    
    .filter(service->Objects.nonNull(service.getType()))
    .filter(service -> (service.getType().isEmpty() || service.getType().equals("Type1")))
    .collect(Collectors.toList());

answered Jun 24, 2022 at 16:17

Sayan Bhattacharya

1,3681 gold badge6 silver badges14 bronze badges

Collectives™ on Stack Overflow

Java stream filter null pointer issue

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related