import foo.*; class Some { void foo() { NotNullClass.foo(null); NotNullClass.foo("a"); NullableClass.foo(null); NullableClass.foo("a"); AnotherPackageNotNull.foo(null); AnotherPackageNotNull.foo("a"); } } @javax.annotation.ParametersAreNonnullByDefault class CheckLoop { void foo(Iterable it) { for (String s : it) { if (s == null) { // it's not ElementType.PARAMETER, no warning here System.out.println(); } } } } @javax.annotation.ParametersAreNonnullByDefault class NotNullClass { static void foo(String s) {} } @javax.annotation.ParametersAreNullableByDefault class NullableClass { static void foo(String s) {} }