SystemUtil (checker-framework 3.21.0 API)

java.lang.Object
- org.checkerframework.javacutil.SystemUtil

```
public class SystemUtil
extends Object
```
This file contains basic utility functions.

Constructor Summary

Constructors
Constructor and Description

SystemUtil()

Constructors
Constructor and Description
`SystemUtil()`

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static <T> void`	`addWithoutDuplicates(List<T> dest, List<? extends T> source)` Adds, to dest, all the elements of source that are not already in dest.
`static <T> T[]`	`concatenate(T[] array1, T... array2)` Deprecated. use StringsPlume.concatenate
`static <T> T[]`	`concatenate(T firstElt, T[] array, T lastElt)` Deprecated. use PlumeUtil.concat
`static boolean`	`getBooleanSystemProperty(String key)` Deprecated. use UtilPlume.getBooleanSystemProperty
`static boolean`	`getBooleanSystemProperty(String key, boolean defaultValue)` Deprecated. use UtilPlume.getBooleanSystemProperty
`static int`	`getJreVersion()` Returns the major JRE version.
`static @Nullable String`	`getReleaseValue(ProcessingEnvironment env)` Returns the release value passed to the compiler or null if release was not passed.
`static @Nullable String`	`getToolsJar()` Returns the pathname to the tools.jar file, or null if it does not exist.
`static <T> List<T>`	`intersection(List<? extends T> list1, List<? extends T> list2)` Returns a list that contains all the elements that are in both lists: that is, the set difference of the two arguments.
`static int`	`mapCapacity(Collection<?> c)` Deprecated. use CollectionsPlume.mapCapacity
`static int`	`mapCapacity(int numElements)` Deprecated. use CollectionsPlume.mapCapacity
`static int`	`mapCapacity(Map<?,?> m)` Deprecated. use CollectionsPlume.mapCapacity
`static List<String>`	`readFile(File argFile)` Deprecated. use Files.readAllLines
`static void`	`sleep(long millis)` Deprecated. use SystemPlume.sleep
`static <T> List<T>`	`union(List<T> list1, List<T> list2)` Returns a list that contains all the distinct elements of the two lists: that is, the union of the two arguments.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SystemUtil
```
public SystemUtil()
```
- Method Detail
  - getJreVersion
```
public static int getJreVersion()
```
    Returns the major JRE version.
    This is different from the version passed to the compiler via --release; use getReleaseValue(ProcessingEnvironment) to get that version.
    Extract the major version number from the "java.version" system property. Two possible formats are considered. Up to Java 8, from a version string like `1.8.whatever`, this method extracts 8. Since Java 9, from a version string like `11.0.1`, this method extracts 11.
    
    Returns:
    
    the major version number from "java.version"
  - getReleaseValue
```
public static @Nullable String getReleaseValue(ProcessingEnvironment env)
```
    Returns the release value passed to the compiler or null if release was not passed.
    
    Parameters:
    
    env - the ProcessingEnvironment
    
    Returns:
    
    the release value or null if none was passed
  - getToolsJar
```
public static @Nullable String getToolsJar()
```
    Returns the pathname to the tools.jar file, or null if it does not exist. Returns null on Java 9 and later.
    
    Returns:
    
    the pathname to the tools.jar file, or null
  - union
```
public static <T> List<T> union(List<T> list1,
                                List<T> list2)
```
    Returns a list that contains all the distinct elements of the two lists: that is, the union of the two arguments.
    For very short lists, this is likely more efficient than creating a set and converting back to a list.
    
    Type Parameters:
    
    T - the type of the list elements
    
    Parameters:
    
    list1 - a list
    
    list2 - a list
    
    Returns:
    
    a list that contains all the distinct elements of the two lists
  - addWithoutDuplicates
```
public static <T> void addWithoutDuplicates(List<T> dest,
                                            List<? extends T> source)
```
    Adds, to dest, all the elements of source that are not already in dest.
    For very short lists, this is likely more efficient than creating a set and converting back to a list.
    
    Type Parameters:
    
    T - the type of the list elements
    
    Parameters:
    
    dest - a list to add to
    
    source - a list of elements to add
  - intersection
```
public static <T> List<T> intersection(List<? extends T> list1,
                                       List<? extends T> list2)
```
    Returns a list that contains all the elements that are in both lists: that is, the set difference of the two arguments.
    For very short lists, this is likely more efficient than creating a set and converting back to a list.
    
    Type Parameters:
    
    T - the type of the list elements
    
    Parameters:
    
    list1 - a list
    
    list2 - a list
    
    Returns:
    
    a list that contains all the elements of list1 that are not in list2
  - readFile
```
@Deprecated
public static List<String> readFile(File argFile)
                                         throws IOException
```
    Deprecated. use Files.readAllLines
    
    Return a list of Strings, one per line of the file.
    
    Parameters:
    
    argFile - argument file
    
    Returns:
    
    a list of Strings, one per line of the file
    
    Throws:
    
    IOException - when reading the argFile
  - sleep
```
@Deprecated
public static void sleep(long millis)
```
    Deprecated. use SystemPlume.sleep
    
    Like Thread.sleep, but does not throw any exceptions, so it is easier for clients to use. Causes the currently executing thread to sleep (temporarily cease execution) for the specified number of milliseconds.
    
    Parameters:
    
    millis - the length of time to sleep in milliseconds
  - concatenate
```
@Deprecated
public static <T> T[] concatenate(T firstElt,
                                              T[] array,
                                              T lastElt)
```
    Deprecated. use PlumeUtil.concat
    
    Concatenates an element, an array, and an element.
    
    Type Parameters:
    
    T - the type of the array elements
    
    Parameters:
    
    firstElt - the first element
    
    array - the array
    
    lastElt - the last elemeent
    
    Returns:
    
    a new array containing first element, the array, and the last element, in that order
  - getBooleanSystemProperty
```
@Deprecated
public static boolean getBooleanSystemProperty(String key)
```
    Deprecated. use UtilPlume.getBooleanSystemProperty
    
    Return true if the system property is set to "true". Return false if the system property is not set or is set to "false". Otherwise, errs.
    
    Parameters:
    
    key - system property to check
    
    Returns:
    
    true if the system property is set to "true". Return false if the system property is not set or is set to "false". Otherwise, errs.
  - getBooleanSystemProperty
```
@Deprecated
public static boolean getBooleanSystemProperty(String key,
                                                           boolean defaultValue)
```
    Deprecated. use UtilPlume.getBooleanSystemProperty
    
    Return its boolean value if the system property is set. Return defaultValue if the system property is not set. Errs if the system property is set to a non-boolean value.
    
    Parameters:
    
    key - system property to check
    
    defaultValue - value to use if the property is not set
    
    Returns:
    
    the boolean value of key or defaultValue if key is not set
  - concatenate
```
@Deprecated
public static <T> T[] concatenate(T[] array1,
                                              T... array2)
```
    Deprecated. use StringsPlume.concatenate
    
    Concatenates two arrays. Can be invoked varargs-style.
    
    Type Parameters:
    
    T - the type of the array elements
    
    Parameters:
    
    array1 - the first array
    
    array2 - the second array
    
    Returns:
    
    a new array containing the contents of the given arrays, in order
  - mapCapacity
```
@Deprecated
public static int mapCapacity(int numElements)
```
    Deprecated. use CollectionsPlume.mapCapacity
    
    Given an expected number of elements, returns the capacity that should be passed to a HashMap or HashSet constructor, so that the set or map will not resize.
    
    Parameters:
    
    numElements - the maximum expected number of elements in the map or set
    
    Returns:
    
    the initial capacity to pass to a HashMap or HashSet constructor
  - mapCapacity
```
@Deprecated
public static int mapCapacity(Collection<?> c)
```
    Deprecated. use CollectionsPlume.mapCapacity
    
    Given an expected number of elements, returns the capacity that should be passed to a HashMap or HashSet constructor, so that the set or map will not resize.
    
    Parameters:
    
    c - a collection whose size is the maximum expected number of elements in the map or set
    
    Returns:
    
    the initial capacity to pass to a HashMap or HashSet constructor
  - mapCapacity
```
@Deprecated
public static int mapCapacity(Map<?,?> m)
```
    Deprecated. use CollectionsPlume.mapCapacity
    
    Given an expected number of elements, returns the capacity that should be passed to a HashMap or HashSet constructor, so that the set or map will not resize.
    
    Parameters:
    
    m - a map whose size is the maximum expected number of elements in the map or set
    
    Returns:
    
    the initial capacity to pass to a HashMap or HashSet constructor

Class SystemUtil

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SystemUtil

Method Detail

getJreVersion

getReleaseValue

getToolsJar

union

addWithoutDuplicates

intersection

readFile

sleep

concatenate

getBooleanSystemProperty

getBooleanSystemProperty

concatenate

mapCapacity

mapCapacity

mapCapacity