The type of the ternary conditional operator is determined by the types of its 2nd and 3rd operands.
In the case of
input == null ? null : 1
the type is Integer, which can be assigned both null and 1.
The compiler allows your method to return an Integer since it can be auto-unboxed into an int, so it fit the int return type of myMethod.
The fact that your specific code may throw a NullPointerException is not something the compiler can detect.
