Module java.base
Package java.lang

## Class StackTraceElement

- java.lang.Object
- - java.lang.StackTraceElement

- All Implemented Interfaces:
    `Serializable`

      public final class StackTraceElement
      extends Object
      implements Serializable

  An element in a stack trace, as returned by `Throwable.getStackTrace()`. Each element represents a single stack frame. All stack frames except for the one at the top of the stack represent a method invocation. The frame at the top of the stack represents the execution point at which the stack trace was generated. Typically, this is the point at which the throwable corresponding to the stack trace was created.
  Since:
    1.4
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `StackTraceElement​(String declaringClass, String methodName, String fileName, int lineNumber)` | Creates a stack trace element representing the specified execution point.
    `StackTraceElement​(String classLoaderName, String moduleName, String moduleVersion, String declaringClass, String methodName, String fileName, int lineNumber)` | Creates a stack trace element representing the specified execution point.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `boolean` | `equals​(Object obj)` | Returns true if the specified object is another `StackTraceElement` instance representing the same execution point as this instance.
    `String` | `getClassLoaderName​()` | Returns the name of the class loader of the class containing the execution point represented by this stack trace element.
    `String` | `getClassName​()` | Returns the fully qualified name of the class containing the execution point represented by this stack trace element.
    `String` | `getFileName​()` | Returns the name of the source file containing the execution point represented by this stack trace element.
    `int` | `getLineNumber​()` | Returns the line number of the source line containing the execution point represented by this stack trace element.
    `String` | `getMethodName​()` | Returns the name of the method containing the execution point represented by this stack trace element.
    `String` | `getModuleName​()` | Returns the module name of the module containing the execution point represented by this stack trace element.
    `String` | `getModuleVersion​()` | Returns the module version of the module containing the execution point represented by this stack trace element.
    `int` | `hashCode​()` | Returns a hash code value for this stack trace element.
    `boolean` | `isNativeMethod​()` | Returns true if the method containing the execution point represented by this stack trace element is a native method.
    `String` | `toString​()` | Returns a string representation of this stack trace element.

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### StackTraceElement

          public StackTraceElement​(String declaringClass,
                                   String methodName,
                                   String fileName,
                                   int lineNumber)

      Creates a stack trace element representing the specified execution point. The `module name` and `module version` of the stack trace element will be `null`.
      Parameters:
        `declaringClass` - the fully qualified name of the class containing the execution point represented by the stack trace element
        `methodName` - the name of the method containing the execution point represented by the stack trace element
        `fileName` - the name of the file containing the execution point represented by the stack trace element, or `null` if this information is unavailable
        `lineNumber` - the line number of the source line containing the execution point represented by this stack trace element, or a negative number if this information is unavailable. A value of -2 indicates that the method containing the execution point is a native method
      Throws:
        `NullPointerException` - if `declaringClass` or `methodName` is null
      Since:
        1.5

    - #### StackTraceElement

          public StackTraceElement​(String classLoaderName,
                                   String moduleName,
                                   String moduleVersion,
                                   String declaringClass,
                                   String methodName,
                                   String fileName,
                                   int lineNumber)

      Creates a stack trace element representing the specified execution point.
      Parameters:
        `classLoaderName` - the class loader name if the class loader of the class containing the execution point represented by the stack trace is named; otherwise `null`
        `moduleName` - the module name if the class containing the execution point represented by the stack trace is in a named module; otherwise `null`
        `moduleVersion` - the module version if the class containing the execution point represented by the stack trace is in a named module that has a version; otherwise `null`
        `declaringClass` - the fully qualified name of the class containing the execution point represented by the stack trace element
        `methodName` - the name of the method containing the execution point represented by the stack trace element
        `fileName` - the name of the file containing the execution point represented by the stack trace element, or `null` if this information is unavailable
        `lineNumber` - the line number of the source line containing the execution point represented by this stack trace element, or a negative number if this information is unavailable. A value of -2 indicates that the method containing the execution point is a native method
      Throws:
        `NullPointerException` - if `declaringClass` is `null` or `methodName` is `null`
      Since:
        9

  - ### Method Detail

    - #### getFileName

          public String getFileName​()

      Returns the name of the source file containing the execution point represented by this stack trace element. Generally, this corresponds to the `SourceFile` attribute of the relevant `class` file (as per The Java Virtual Machine Specification, Section 4.7.7). In some systems, the name may refer to some source code unit other than a file, such as an entry in source repository.
      Returns:
        the name of the file containing the execution point represented by this stack trace element, or `null` if this information is unavailable.

    - #### getLineNumber

          public int getLineNumber​()

      Returns the line number of the source line containing the execution point represented by this stack trace element. Generally, this is derived from the `LineNumberTable` attribute of the relevant `class` file (as per The Java Virtual Machine Specification, Section 4.7.8).
      Returns:
        the line number of the source line containing the execution point represented by this stack trace element, or a negative number if this information is unavailable.

    - #### getModuleName

          public String getModuleName​()

      Returns the module name of the module containing the execution point represented by this stack trace element.
      Returns:
        the module name of the `Module` containing the execution point represented by this stack trace element; `null` if the module name is not available.
      Since:
        9
      See Also:
        `Module.getName()`

    - #### getModuleVersion

          public String getModuleVersion​()

      Returns the module version of the module containing the execution point represented by this stack trace element.
      Returns:
        the module version of the `Module` containing the execution point represented by this stack trace element; `null` if the module version is not available.
      Since:
        9
      See Also:
        `ModuleDescriptor.Version`

    - #### getClassLoaderName

          public String getClassLoaderName​()

      Returns the name of the class loader of the class containing the execution point represented by this stack trace element.
      Returns:
        the name of the class loader of the class containing the execution point represented by this stack trace element; `null` if the class loader is not named.
      Since:
        9
      See Also:
        `ClassLoader.getName()`

    - #### getClassName

          public String getClassName​()

      Returns the fully qualified name of the class containing the execution point represented by this stack trace element.
      Returns:
        the fully qualified name of the `Class` containing the execution point represented by this stack trace element.

    - #### getMethodName

          public String getMethodName​()

      Returns the name of the method containing the execution point represented by this stack trace element. If the execution point is contained in an instance or class initializer, this method will return the appropriate special method name, `<init>` or `<clinit>`, as per Section 3.9 of The Java Virtual Machine Specification.
      Returns:
        the name of the method containing the execution point represented by this stack trace element.

    - #### isNativeMethod

          public boolean isNativeMethod​()

      Returns true if the method containing the execution point represented by this stack trace element is a native method.
      Returns:
        `true` if the method containing the execution point represented by this stack trace element is a native method.

    - #### toString

          public String toString​()

      Returns a string representation of this stack trace element.
      Overrides:
        `toString` in class `Object`
      API Note:
        The format of this string depends on the implementation, but the following examples may be regarded as typical:
        - "`com.foo.loader/foo@9.0/com.foo.Main.run(Main.java:101)`" - See the description below.
        - "`com.foo.loader/foo@9.0/com.foo.Main.run(Main.java)`" - The line number is unavailable.
        - "`com.foo.loader/foo@9.0/com.foo.Main.run(Unknown Source)`" - Neither the file name nor the line number is available.
        - "`com.foo.loader/foo@9.0/com.foo.Main.run(Native Method)`" - The method containing the execution point is a native method.
        - "`com.foo.loader//com.foo.bar.App.run(App.java:12)`" - The class of the execution point is defined in the unnamed module of the class loader named `com.foo.loader`.
        - "`acme@2.1/org.acme.Lib.test(Lib.java:80)`" - The class of the execution point is defined in `acme` module loaded by by a built-in class loader such as the application class loader.
        - "`MyClass.mash(MyClass.java:9)`" - `MyClass` class is on the application class path.

        The first example shows a stack trace element consisting of three elements, each separated by `"/"` followed with the source file name and the line number of the source line containing the execution point. The first element "`com.foo.loader`" is the name of the class loader. The second element "`foo@9.0`" is the module name and version. The third element is the method containing the execution point; "`com.foo.Main"`" is the fully-qualified class name and "`run`" is the name of the method. "`Main.java`" is the source file name and "`101`" is the line number.

        If a class is defined in an unnamed module then the second element is omitted as shown in "`com.foo.loader//com.foo.bar.App.run(App.java:12)`".

        If the class loader is a built-in class loader or is not named then the first element and its following `"/"` are omitted as shown in "`acme@2.1/org.acme.Lib.test(Lib.java:80)`". If the first element is omitted and the module is an unnamed module, the second element and its following `"/"` are also omitted as shown in "`MyClass.mash(MyClass.java:9)`".

        The `toString` method may return two different values on two `StackTraceElement` instances that are equal, for example one created via the constructor, and one obtained from `Throwable` or `StackWalker.StackFrame`, where an implementation may choose to omit some element in the returned string.

      Returns:
        a string representation of the object.
      See Also:
        `Throwable.printStackTrace()`

    - #### equals

          public boolean equals​(Object obj)

      Returns true if the specified object is another `StackTraceElement` instance representing the same execution point as this instance. Two stack trace elements `a` and `b` are equal if and only if:

               equals(a.getClassLoaderName(), b.getClassLoaderName()) &&
               equals(a.getModuleName(), b.getModuleName()) &&
               equals(a.getModuleVersion(), b.getModuleVersion()) &&
               equals(a.getClassName(), b.getClassName()) &&
               equals(a.getMethodName(), b.getMethodName())
               equals(a.getFileName(), b.getFileName()) &&
               a.getLineNumber() == b.getLineNumber()

      where `equals` has the semantics of `Objects.equals`.
      Overrides:
        `equals` in class `Object`
      Parameters:
        `obj` - the object to be compared with this stack trace element.
      Returns:
        true if the specified object is another `StackTraceElement` instance representing the same execution point as this instance.
      See Also:
        `Object.hashCode()`, `HashMap`

    - #### hashCode

          public int hashCode​()

      Returns a hash code value for this stack trace element.
      Overrides:
        `hashCode` in class `Object`
      Returns:
        a hash code value for this object.
      See Also:
        `Object.equals(java.lang.Object)`, `System.identityHashCode(java.lang.Object)`