jni调用java静态方法时总是报错这个 不知道为什么

D:\sgmuserprofile\Public\soft\android-studio\bin

Error:(19, 11) error: expected ';' after expression

Error:(19, 12) error: use of undeclared identifier 'cls_hello'

Error:(20, 8) error: use of undeclared identifier 'cls_hello'

Error:(25, 56) error: use of undeclared identifier 'cls_hello'

Warning:(30, 65) warning: adding 'jint' (aka 'int') to a string does not append to the string [-Wstring-plus-int]

Error:(35, 31) error: use of undeclared identifier 'cls_hello'

Error:(37, 25) error: use of undeclared identifier 'cls_hello'