devonfw#739: created new exception and added statement

Added a new statement that checks if IDE_ROOT == null in EnvironmentCommanlet method. If so, it throws an empty exception

cli/src/main/java/com/devonfw/tools/ide/cli/NullIdeRootException.java

@@ -0,0 +1,15 @@
+package com.devonfw.tools.ide.cli;
+
+/**
+ * {@link CliException} that is thrown if IDE_ROOT == null
+ */
+public class NullIdeRootException extends CliException {
+
+  /**
+   * The constructor.
+   */
+  public NullIdeRootException() {
+
+    super("");
+  }
+}

cli/src/main/java/com/devonfw/tools/ide/commandlet/EnvironmentCommandlet.java

@@ -5,6 +5,7 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 
+import com.devonfw.tools.ide.cli.NullIdeRootException;
 import com.devonfw.tools.ide.context.AbstractIdeContext;
 import com.devonfw.tools.ide.context.IdeContext;
 import com.devonfw.tools.ide.environment.EnvironmentVariablesType;
@@ -52,7 +53,9 @@ public boolean isProcessableOutput() {
 
   @Override
   public void run() {
-
+    if (context.getIdeRoot() == null) {
+      throw new NullIdeRootException();
+    }
     boolean winCmd = false;
     WindowsPathSyntax pathSyntax = null;
     if (this.context.getSystemInfo().isWindows()) {