=== which are checked? ===
Exception                    CHECKED    Exception -> Throwable -> Object
IOException                  CHECKED    IOException -> Exception -> Throwable -> Object
InterruptedException         CHECKED    InterruptedException -> Exception -> Throwable -> Object
RuntimeException             unchecked  RuntimeException -> Exception -> Throwable -> Object
IllegalArgumentException     unchecked  IllegalArgumentException -> RuntimeException -> Exception -> Throwable -> Object
NullPointerException         unchecked  NullPointerException -> RuntimeException -> Exception -> Throwable -> Object
Error                        unchecked  Error -> Throwable -> Object
OutOfMemoryError             unchecked  OutOfMemoryError -> VirtualMachineError -> Error -> Throwable -> Object
StackOverflowError           unchecked  StackOverflowError -> VirtualMachineError -> Error -> Throwable -> Object

=== checked exception inside a stream lambda: wrap in UncheckedIOException ===
contents of a.txt
caught: java.io.UncheckedIOException: java.io.IOException: cannot read bad.txt
original cause: java.io.IOException: cannot read bad.txt