JDK 11.0.2 compilation fails with javac NPE on anonymous parameterized class type inference

Question

Code (spring-web 5.1.2)

public static void main(String[] args) {
    RestTemplate restTemplate = new RestTemplate();

    HttpHeaders headers = new HttpHeaders();
    headers.set(HttpHeaders.AUTHORIZATION, "token");
    HttpEntity<Object> requestEntity = new HttpEntity<>(headers);

    ResponseEntity<Object> test = restTemplate.exchange(
            "https://example.com",
            HttpMethod.GET,
            new HttpEntity<>(headers),
            new ParameterizedTypeReference<>() { // fails here
            });
}

OracleJDK 1.8 (expected output)

cannot infer type arguments for org.springframework.core.ParameterizedTypeReference

reason: cannot use '<>' with anonymous inner classes

OracleJDK 11.0.2 (not expected output)

compiler message file broken: key=compiler.misc.msg.bug arguments=11.0.2, {1}, {2}, {3}, {4}, {5}, {6}, {7} java.lang.NullPointerException at jdk.compiler/com.sun.tools.javac.comp.Flow$FlowAnalyzer.visitApply(Flow.java:1235) at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1634) at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49) at jdk.compiler/com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:398) at jdk.compiler/com.sun.tools.javac.comp.Flow$FlowAnalyzer.visitVarDef(Flow.java:989)
...

If I change diamond operator to explicit type

new ParameterizedTypeReference<>(){} to new ParameterizedTypeReference<Object>(){}

then the code compiles successfully on both JDKs.

Is it a known compiler bug?

Nakasuji

An exception from the compiler is a bug. Write up a test case and submit the bug. – Pothole

I confirm this bug as well – Leucoma

I am not able to build the project while my other team mates are able to build it . I tried to delete my repo . no luck . – Hedgepeth

This is a bug in any version older than 11.0.8. Try upgrading your JDK to 11.0.8 or newer – Landa

JDK 11.0.14 works, haven't tried earlier versions. – Tobytobye

JDK 11.0.15 also worked for me – Corruption

Answer 1

Bug (JDK-8212586) has been already submitted and fixed in version 12.

Minimal, verifiable example:

public static void main(String[] args) {
    new Bug<>(){};
}

static class Bug<T> {

    Bug() {
        test(new ParameterizedTypeReference<>(){});
    }

    void test(ParameterizedTypeReference<T> typeReference) {
    }
}

Some Details.

---

Fix has been also backported to JDK 11 - https://bugs.openjdk.java.net/browse/JDK-8220578.

Available starting JDK 11.0.4.

Nakasuji

Does "fixed in version 12" mean that I need to install JDK 12 to get the fix? Will JDK 11 remain broken? – Bayonne

@TroyDaniels yes fix is included and scheduled to be released as part of JDK 12. openjdk.java.net/projects/jdk/12 – Nakasuji

what about JDK11 which "supposed" to be LTE? – Leucoma

@MirceaStanciu fix has been backported and will be available in JDK 11.0.4. Updated the answer. – Nakasuji

java 11.0.6 has the same problem – Maureenmaureene

Some consusion about versions: in openjdk it is fixed 11.0.4 onwards, oracle jdk 11.0.8. See original bug report link. – Swell

thanks this post saved me,was unable to figure out wats wrong,literally no stack trace pointing to this change – Sami

Answer 2

As pointed out in previous comments, the problem is with parametrized anonymous classes, e.g. when using TypeToken from Guava, this does NOT work:

public List<SomeClass> list() {
    return getData(new TypeToken<>() { });
}

But this DOES work:

public List<SomeClass> list() {
    return getData(new TypeToken<List<SomeClass>>() { });
}

I tried that in versions 11.0.3 - 11.0.7 versions and all contains the bug.

Heartrending

OpenJDK 11.0.8 has the bug too – Dariusdarjeeling

I did with 11.0.12 and it works. – Piteous

Answer 3

I Had the same error,you need to create a function :

ParameterizedTypeReference<Object> createParameterizedTypeReference(){ return new ParameterizedTypeReference<>(){}; }

and call it :

ResponseEntity<Object> test = restTemplate.exchange(
"https://example.com",
HttpMethod.GET,
new HttpEntity<>(headers),
createParameterizedTypeReference() { 
});

Dunkle

Answer 4

Java 11.0.7 has the same problem.

This changed from:

new ParameterizedTypeReference<>() {
})

to this:

new ParameterizedTypeReference<HashMap<String, MyClass>>() {
})

Untinged

Answer 5

I've fixed this problem on my machine by upgrading to AdoptOpenJDK 11.0.8.

https://adoptopenjdk.net/installation.html#x64_mac-jdk

Kopple

Answer 6

Most of the times, this error doesn't tell you the originating class so it's very hard to intentionally reproduce the problem. After trying a lot, I finally updated project JDK to 11.0.16 (from 11.0.7) and it worked!

Sudduth

Answer 7

In case anyone else faces this issue: we had to change the java compiler from javac to eclipse (anything else that's not javac) to get our code to compile. Upgrading/downgrading jdk didn't fix the issue for us.

Bills

Answer 8

In my case I intalled latest java 11 from oracle (Java SE Development Kit 11.0.19) and it solved problem. You can download latest version here : https://www.oracle.com/pl/java/technologies/javase/jdk11-archive-downloads.html

Ayers