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Java

Java static code analysis

Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your JAVA code

  • All rules 733
  • Vulnerability60
  • Bug175
  • Security Hotspot40
  • Code Smell458

  • Quick Fix 65
Filtered: 9 rules found
java16
    Impact
      Clean code attribute
        1. 'serialVersionUID' field should not be set to '0L' in records

           Code Smell
        2. Equals method should be overridden in records containing array fields

           Bug
        3. Reflection should not be used to increase accessibility of records' fields

           Bug
        4. Custom getter method should not be used to override record's getter behavior

           Code Smell
        5. Members ignored during record serialization should not be used

           Bug
        6. Redundant constructors/methods should be avoided in records

           Code Smell
        7. Records should be used instead of ordinary classes when representing immutable data structure

           Code Smell
        8. "Stream.toList()" method should be used instead of "collectors" when unmodifiable list needed

           Code Smell
        9. Pattern Matching for "instanceof" operator should be used instead of simple "instanceof" + cast

           Code Smell

        "Stream.toList()" method should be used instead of "collectors" when unmodifiable list needed

        intentionality - clear
        maintainability
        Code Smell
        • java16

        Why is this an issue?

        In Java 8 Streams were introduced to support chaining of operations over collections in a functional style. The most common way to save a result of such chains is to save them to some collection (usually List). To do so there is a terminal method collect that can be used with a library of Collectors. The key problem is that .collect(Collectors.toList()) actually returns a mutable kind of List while in the majority of cases unmodifiable lists are preferred. In Java 10 a new collector appeared to return an unmodifiable list: toUnmodifiableList(). This does the trick but results in verbose code. Since Java 16 there is now a better variant to produce an unmodifiable list directly from a stream: Stream.toList().

        This rule raises an issue when "collect" is used to create a list from a stream.

        Noncompliant code example

        List<String> list1 = Stream.of("A", "B", "C")
                                   .collect(Collectors.toList()); // Noncompliant
        
        List<String> list2 = Stream.of("A", "B", "C")
                                   .collect(Collectors.toUnmodifiableList()); // Noncompliant
        

        Compliant solution

        List<String> list1 = Stream.of("A", "B", "C").toList(); // Compliant
        
        List<String> list2 = Stream.of("A", "B", "C")
                                   .collect(Collectors.toList()); // Compliant, the list2 needs to be mutable
        
        list2.add("X");
        
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