Multiple null checks in Java 8

You may do it like so:

String s = Stream.of(str1, str2, str3)
    .filter(Objects::nonNull)
    .findFirst()
    .orElse(str4);

How about ternary conditional operator?

String s = 
    str1 != null ? str1 : 
    str2 != null ? str2 : 
    str3 != null ? str3 : str4
;