Try to compile following codes.

import java.util.function.Supplier;
import java.util.stream.Stream;

public class Issue {
    public static void main(String[] args) {
        System.out.println(new Issue().getList().get());
    }

    Supplier<TT> getList() {
        return () -> Stream.of(1).map(TT::new).findFirst().get();
    }

    class TT {
        public TT(int i) {

        }
    }
}
////////////////////////////////////
import java.util.function.Function;
import java.util.stream.Stream;

public class Issue {
    public static void main(String[] args) {
        System.out.println(new Issue().map().apply(1));
    }

    Function<Integer,TT> map() {
        return (i) -> Stream.of(i).map(TT::new).findFirst().get();
    }

    class TT {
        public TT(int i) {

        }
    }
}

//////////////////////////////////////////
java.lang.NullPointerException
        at com.sun.tools.javac.jvm.Code.emitop0(Code.java:563)
        at com.sun.tools.javac.jvm.Items$SelfItem.load(Items.java:367)
        at com.sun.tools.javac.jvm.Gen.genArgs(Gen.java:966)
        at com.sun.tools.javac.jvm.Gen.visitApply(Gen.java:1905)
        at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1459)
        at com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:947)
        at com.sun.tools.javac.jvm.Gen.genArgs(Gen.java:966)
        at com.sun.tools.javac.jvm.Gen.visitApply(Gen.java:1905)
        at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1459)
        at com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:947)
        at com.sun.tools.javac.jvm.Gen.visitSelect(Gen.java:2404)
        at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:1891)
        at com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:947)
        at com.sun.tools.javac.jvm.Gen.visitApply(Gen.java:1900)
        at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1459)
        at com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:947)
        at com.sun.tools.javac.jvm.Gen.visitTypeCast(Gen.java:2327)
        at com.sun.tools.javac.tree.JCTree$JCTypeCast.accept(JCTree.java:1808)
        at com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:947)
        at com.sun.tools.javac.jvm.Gen.visitReturn(Gen.java:1863)
        at com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1378)
        at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:737)
        at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:772)
        at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:758)
        at com.sun.tools.javac.jvm.Gen.genStats(Gen.java:809)
        at com.sun.tools.javac.jvm.Gen.visitBlock(Gen.java:1158)
        at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:903)
        at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:737)
        at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:772)
        at com.sun.tools.javac.jvm.Gen.genMethod(Gen.java:1031)
        at com.sun.tools.javac.jvm.Gen.visitMethodDef(Gen.java:994)
        at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:772)
        at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:737)
        at com.sun.tools.javac.jvm.Gen.genClass(Gen.java:2526)
        at com.sun.tools.javac.main.JavaCompiler.genCode(JavaCompiler.java:748)
        at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1570)
        at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1534)
        at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:904)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:863)
        at com.sun.tools.javac.main.Main.compile(Main.java:523)
        at com.sun.tools.javac.main.Main.compile(Main.java:381)
        at com.sun.tools.javac.main.Main.compile(Main.java:370)
        at com.sun.tools.javac.main.Main.compile(Main.java:361)
        at com.sun.tools.javac.Main.compile(Main.java:56)
        at com.sun.tools.javac.Main.main(Main.java:42)

Exception in thread "main" java.lang.VerifyError: Bad type on operand stack
Exception Details:
  Location:
    Issue.lambda$map$0(Ljava/lang/Integer;)LIssue$TT; @5: invokedynamic
  Reason:
    Type 'java/lang/Integer' (current frame, stack[1]) is not assignable to 'Issue'
  Current Frame:
    bci: @5
    flags: { }
    locals: { 'java/lang/Integer' }
    stack: { 'java/util/stream/Stream', 'java/lang/Integer' }
  Bytecode:
    0000000: 2ab8 000a 2aba 000b 0000 b900 0c02 00b9
    0000010: 000d 0100 b600 0ec0 000f b0