Since: PMD 0.5
Duplicate or overlapping import statements should be avoided.
This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.imports.DuplicateImportsRule
Example(s):import java.lang.String; import java.lang.*; public class Foo {}
This rule has the following properties:
Name | Default Value | Description |
---|---|---|
violationSuppressRegex | Suppress violations with messages matching a regular expression | |
violationSuppressXPath | Suppress violations on nodes which match a given relative XPath expression. |
Since: PMD 0.5
Avoid importing anything from the package 'java.lang'. These classes are automatically imported (JLS 7.5.3).
This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.imports.DontImportJavaLangRule
Example(s):import java.lang.String; // this is unnecessary public class Foo {} // --- in another source code file... import java.lang.*; // this is bad public class Foo {}
This rule has the following properties:
Name | Default Value | Description |
---|---|---|
violationSuppressRegex | Suppress violations with messages matching a regular expression | |
violationSuppressXPath | Suppress violations on nodes which match a given relative XPath expression. |
Since: PMD 1.0
Avoid the use of unused import statements to prevent unwanted dependencies.
This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.imports.UnusedImportsRule
Example(s):// this is bad import java.io.File; public class Foo {}
This rule has the following properties:
Name | Default Value | Description |
---|---|---|
violationSuppressRegex | Suppress violations with messages matching a regular expression | |
violationSuppressXPath | Suppress violations on nodes which match a given relative XPath expression. |
Since: PMD 1.02
There is no need to import a type that lives in the same package.
This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.imports.ImportFromSamePackageRule
Example(s):package foo; import foo.Buz; // no need for this import foo.*; // or this public class Bar{}
This rule has the following properties:
Name | Default Value | Description |
---|---|---|
violationSuppressRegex | Suppress violations with messages matching a regular expression | |
violationSuppressXPath | Suppress violations on nodes which match a given relative XPath expression. |
Since: PMD 4.1
If you overuse the static import feature, it can make your program unreadable and unmaintainable, polluting its namespace with all the static members you import. Readers of your code (including you, a few months after you wrote it) will not know which class a static member comes from (Sun 1.5 Language Guide).
.[count(ImportDeclaration[@Static = 'true']) > $maximumStaticImports]
import static Lennon; import static Ringo; import static George; import static Paul; import static Yoko; // Too much !
This rule has the following properties:
Name | Default Value | Description |
---|---|---|
maximumStaticImports | 4 | All static imports can be disallowed by setting this to 0 |
Since: PMD 5.0
Import statements allow the use of non-fully qualified names. The use of a fully qualified name which is covered by an import statement is redundant. Consider using the non-fully qualified name.
This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.imports.UnnecessaryFullyQualifiedNameRule
Example(s):import java.util.List; public class Foo { private java.util.List list1; // Unnecessary FQN private List list2; // More appropriate given import of 'java.util.List' }
This rule has the following properties:
Name | Default Value | Description |
---|---|---|
violationSuppressRegex | Suppress violations with messages matching a regular expression | |
violationSuppressXPath | Suppress violations on nodes which match a given relative XPath expression. |