The clearProperty()
function from java.lang.*
in the System
class removes the system property that is specified by the defined key.
static String clearProperty(String key)
clearProperty()
takes a string type variable:
key
: The name of the system property that has to be removed.clearProperty()
function returns the string value previously linked with the system property.null
if there is no property with the defined key.NullPointerException
is thrown if the value of the key is null
.IllegalArgumentException
is thrown if the key is empty.The code below demonstrates how the clearProperty()
method works. Execute this code to see the output.
// Load basic classes import java.lang.*; public class EdPresso { public static void main(String[] args) { // IT WILL RETURN THE PREVIOUS VALUE REGARDING SYSTEM PROPERTY System.out.println("the initial value is: " + System.getProperty("user.dir")); // it will clear the value String val = System.clearProperty("user.dir"); System.out.println("the returned value is: " + val); System.out.println("the cleared result is: " + System.getProperty("user.dir")); // setting the system property System.setProperty("user.dir", "C:/java"); // getting the system property after making changes by using setProperty System.out.println("the new value is: " + System.getProperty("user.dir")); } }
In the code above, we use clearProperty()
to display and remove the initial value of the system property. The return value of the function that stores the previous value is then displayed, which matches the initial value. A new value is set for the property and is displayed.
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