Adobe-Consulting-Services/acs-aem-commons

        Class valueType = val.getClass();

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Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

    Class getBaseType() {

Close

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

    private Class baseType = null;

Close

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

            switch (cellType) {
                case BOOLEAN:
                    setValue(cell.getBooleanCellValue());
                    break;
                case NUMERIC:

Close

A reference to null should never be dereferenced/accessed. Doing so will cause a NullPointerException to be thrown. At best, such an exception will cause abrupt program termination. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures.

Note that when they are present, this rule takes advantage of @CheckForNull and @Nonnull annotations defined in JSR-305 to understand which values are and are not nullable except when @Nonnull is used on the parameter to equals, which by contract should always work with null.

Noncompliant Code Example

@CheckForNull
String getName(){...}

public boolean isNameEmpty() {
  return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked
}

Connection conn = null;
Statement stmt = null;
try{
  conn = DriverManager.getConnection(DB_URL,USER,PASS);
  stmt = conn.createStatement();
  // ...

}catch(Exception e){
  e.printStackTrace();
}finally{
  stmt.close();   // Noncompliant; stmt could be null if an exception was thrown in the try{} block
  conn.close();  // Noncompliant; conn could be null if an exception was thrown
}

private void merge(@Nonnull Color firstColor, @Nonnull Color secondColor){...}

public  void append(@CheckForNull Color color) {
    merge(currentColor, color);  // Noncompliant; color should be null-checked because merge(...) doesn't accept nullable parameters
}

void paint(Color color) {
  if(color == null) {
    System.out.println("Unable to apply color " + color.toString());  // Noncompliant; NullPointerException will be thrown
    return;
  }
  ...
}

See

• MITRE, CWE-476 - NULL Pointer Dereference
• CERT, EXP34-C. - Do not dereference null pointers
• CERT, EXP01-J. - Do not use a null in a case where an object is required

 * ACS AEM Commons

Close

Checks the header of a source file against a header that contains aregular expression for each line of the source header.

Rationale: In some projects checking against afixed header is not sufficient, e.g. the header might require acopyright line where the year information is not static.

For example, consider the following header:

<source><br>line 1: ^/{71}$<br>line 2: ^// checkstyle:$<br>line 3: ^// Checks Java source code for adherence to a set of rules\.$<br>line 4: ^// Copyright \(C\) \d\d\d\d Oliver Burn$<br>line 5: ^// Last modification by \$Author.*\$$<br>line 6: ^/{71}$<br>line 7:<br>line 8: ^package<br>line 9:<br>line 10: ^import<br>line 11:<br>line 12: ^/\*\*<br>line 13: ^ \*([^/]|$)<br>line 14: ^ \*/<br> </source>

Lines 1 and 6 demonstrate a more compact notation for 71 '/'characters. Line 4 enforces that the copyright notice includes afour digit year. Line 5 is an example how to enforce revisioncontrol keywords in a file header. Lines 12-14 is a template forjavadoc (line 13 is so complicated to remove conflict with and ofjavadoc comment). Lines 7, 9 and 11 will be treated as '^$' andwill forcefully expect the line to be empty.

Different programming languages have different comment syntaxrules, but all of them start a comment with a non-wordcharacter. Hence you can often use the non-word characterclass to abstract away the concrete comment syntax and allowchecking the header for different languages with a singleheader definition. For example, consider the following headerspecification (note that this is not the full Apache licenseheader):

<source><br>line 1: ^#!<br>line 2: ^&lt;\?xml.*&gt;$<br>line 3: ^\W*$<br>line 4: ^\W*Copyright 2006 The Apache Software Foundation or its licensors, as applicable\.$<br>line 5: ^\W*Licensed under the Apache License, Version 2\.0 \(the "License"\);$<br>line 6: ^\W*$<br> </source>

Lines 1 and 2 leave room for technical header lines, e.g. the"#!/bin/sh" line in Unix shell scripts, or the XML file headerof XML files. Set the multiline property to "1, 2" so theselines can be ignored for file types where they do no apply.Lines 3 through 6 define the actual header content. Note howlines 2, 4 and 5 use escapes for characters that have specialregexp semantics.

In default configuration, if header is not specified, the default valueof header is set to null and the check does not rise any violations.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.