Check If Command Line Arguments Are Null in Java (#13246)

core-java-modules/core-java-lang-5/src/main/java/com/baeldung/commandline/CommandLineWithErrorHandling.java

@@ -0,0 +1,12 @@
+package com.baeldung.commandline;
+
+public class CommandLineWithErrorHandling {
+
+    public static void main(String[] args) {
+        if (args.length > 0) {
+            System.out.println(args[0]);
+        } else {
+            System.out.println("No command line arguments were provided.");
+        }
+    }
+}

core-java-modules/core-java-lang-5/src/main/java/com/baeldung/commandline/CommandLineWithoutErrorHandling.java

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+package com.baeldung.commandline;
+
+public class CommandLineWithoutErrorHandling {
+
+    public static void main(String[] args) {
+
+        System.out.println(args[0]);
+    }
+}

core-java-modules/core-java-lang-5/src/test/java/com/baeldung/commandline/CommandLineWithoutErrorHandlingUnitTest.java

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+package com.baeldung.commandline;
+
+import org.junit.Test;
+import static org.junit.Assert.fail;
+
+public class CommandLineWithoutErrorHandlingUnitTest {
+
+    @Test(expected = NullPointerException.class)
+    public void givenNullCommandLineArgument_whenPassedToMainFunction_thenExpectNullPointerException() {
+        CommandLineWithoutErrorHandling.main(null);
+    }
+}