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

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?

javajavactype-inferencejava-11compiler-bug


Solution 1:[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.

Solution 2:[2]

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() { 
});

Solution 3:[3]

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.

Solution 4:[4]

Java 11.0.7 has the same problem.

This changed from:

new ParameterizedTypeReference<>() {
})

to this:

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

Solution 5:[5]

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

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

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Michael
Solution 3 Miri
Solution 4 Václav
Solution 5 bogdancep

Related Questions