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JavaAdvanced#collections#oop
JavaAdvanced#streams#exceptions
What is the difference between checked exception wrapping in streams' lambdas — why can't you throw checked exceptions inside a lambda directly used in a stream?
Functional interfaces used in streams (Function, Consumer, etc.) don't declare checked exceptions in their method signatures, so a lambda implementing them cannot throw a checked exception without wrapping it in a try-catch or an unchecked RuntimeException.
Example
list.stream().map(s -> {
try { return process(s); } // process() throws IOException
catch (IOException e) { throw new RuntimeException(e); } // must wrap as unchecked
});