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Java - how to enable assertions?
14 points
In this article we whould like to show how to enable assertions in Java.
The article describle 2 ways how to do it:
- with command line (terminal),
- with IntelliJ IDE.
Read below sections to see details.
Running program from console it is necessary to add -ea or -enableassertions paramter for java virtual machine to use assertions.
Program.java file:
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public class Program {2
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public static void main(String[] args) {4
String a = "text"; // or = null by default5
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// some code...7
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a = null; // for example: some operation caused null value9
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// some code...11
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assert a != null : "Variable can not be null";13
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System.out.println(a.length());15
}16
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$ javac Program.javaxxxxxxxxxx1
$ java -ea Programor
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$ java -enableassertions ProgramOutput:
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Exception in thread "main" java.lang.AssertionError: Variable can not be null2
at Program.main(Program.java:12)IntelliJ requires to add in Run/Debug Configurations window, -ea or -enableassertions paramter VM Options field.
