Description Manoj N Palat 2021-04-08 05:40:27 EDT

Use the example from 562324 comment 11 - reproduced below:

import java.util.Arrays;
import java.util.List;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collector;

public class X  {

	public static void main(String[] args) {
		List<String> taskNames = Arrays.asList("First", "Second", "Third");
		
		// hover over services
		var services = taskNames.stream().collect(X.toSet(name -> new Y(){}));
    
		String[] names = services.stream().map(e -> e).toArray(String[] :: new);
	}
	
    public static <T, U>
    Collector<T, ?, Set<U>> toSet(Function<? super T, ? extends U> valueMapper) {
    	return null;
    }

}

abstract class Y{}


Hover over services in var services =...
to get an IllegalArgumentException with the following ST:

java.lang.IllegalArgumentException: java.util.Set<new Y(){}>
	at org.eclipse.jdt.core.Signature.checkNextChar(Signature.java:1025)
	at org.eclipse.jdt.core.Signature.encodeTypeSignature(Signature.java:1507)
	at org.eclipse.jdt.core.Signature.createCharArrayTypeSignature(Signature.java:1095)
	at org.eclipse.jdt.core.Signature.createTypeSignature(Signature.java:1293)
	at org.eclipse.jdt.internal.core.SelectionRequestor.acceptLocalVariable(SelectionRequestor.java:488)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.selectFrom(SelectionEngine.java:1393)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.select(SelectionEngine.java:1096)
	at org.eclipse.jdt.internal.core.Openable.codeSelect(Openable.java:167)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:389)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:382)
	at org.eclipse.jdt.internal.ui.text.java.hover.AbstractJavaEditorTextHover.getJavaElementsAt(AbstractJavaEditorTextHover.java:121)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavadocHover.internalGetHoverInfo(JavadocHover.java:662)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavadocHover.getHoverInfo2(JavadocHover.java:658)
	at org.eclipse.jdt.internal.ui.text.java.hover.BestMatchHover.getHoverInfo2(BestMatchHover.java:163)
	at org.eclipse.jdt.internal.ui.text.java.hover.BestMatchHover.getHoverInfo2(BestMatchHover.java:130)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavaEditorTextHoverProxy.getHoverInfo2(JavaEditorTextHoverProxy.java:89)
	at org.eclipse.jface.text.TextViewerHoverManager$1.run(TextViewerHoverManager.java:155)