Thread with Lambda expression
If you intend on running a single method only with no arguments you can replace the lambda with a method reference.
For instance:
Thread t = new Thread(() -> {
foo();
});
can be more succinctly expressed as
Thread t = new Thread(this::foo);
To start it
t.start();
You have created a functional interface Predicate
whose method is declared to throw an InterruptedException
, which is a checked exception. However, you call test()
in the body of a lambda expression as the parameter to the Thread
constructor that takes a Runnable
, whose run()
method is not declared to throw any checked exceptions. Therefore, because the exception is not caught in the body, a compiler error occurs.
Incidentally, it may be confusing to name your own interface Predicate
, because of the built-in functional interface java.util.function.Predicate
whose functional method returns a boolean
.
Because run()
can't throw an Exception
, you must catch
the exception and handle it. You might log the exception and its stack trace. You might wrap the exception in a RuntimeException
. Either way, catching the checked exception will allow the code to compile. Example:
Thread t1 = new Thread(() -> {
try {
prod.test();
} catch (InterruptedException e) {
// handle: log or throw in a wrapped RuntimeException
throw new RuntimeException("InterruptedException caught in lambda", e);
}
});
As @rgettman says, the name Predicate
is unhappy... Anyways, you could take advantage of default
methods in Java:
interface PredicateButPleaseChangeMyName {
void test() throws InterruptedException;
default void tryTest() {
try {
this.test();
} catch (InterruptedException e) {
// handle e (log or wrap in a RuntimeException)
}
}
}
Then, in your main method, simply create the threads by calling the default tryTest()
method:
Thread t1 = new Thread(() -> prod.tryTest());
Thread t2 = new Thread(() -> cons.tryTest());