Check processing is indispensable for creating a program, but here we have summarized the check processing in Java.
Environment: Spring Framework
import java.util.Objects;
class Check {
    void execute() {
        // message == null
        if (Objects.isNull(message)) {
        }
        // message != null
        if (Objects.nonNull(message)) {
        }
        // message ==Throw a NullPointerException if null
        Objects.requireNonNull(message);
    }
}
import org.springframework.util.StringUtils;
class Check {
    void execute() {
        // (message == null || "".equals(message))
        if (StringUtils.isEmpty(message)) {
        }
        // (str != null && !str.isEmpty())
        if (StringUtils.hasLength(message)) {
        }
    }
}
import org.springframework.util.CollectionUtils;
class Check {
    void execute() {
        List<String> list = new ArrayList<>();
        list.add("Hello");
        list.add("World");
        // (list == null || list.isEmpty())
        if (CollectionUtils.isEmpty(list)) {
        }
    }
}
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