diff --git a/FCL/src/main/java/com/tungsten/fcl/activity/ShellActivity.java b/FCL/src/main/java/com/tungsten/fcl/activity/ShellActivity.java
index d90d4f69..eccadf20 100644
--- a/FCL/src/main/java/com/tungsten/fcl/activity/ShellActivity.java
+++ b/FCL/src/main/java/com/tungsten/fcl/activity/ShellActivity.java
@@ -50,9 +50,24 @@ public class ShellActivity extends FCLActivity {
                 if (cmd.endsWith("\n")) {
                     logWindow.appendLog("->" + cmd);
                     editText.setText("");
+                    String javaDir = FCLPath.RUNTIME_DIR + "/java";
                     if (cmd.contains("clear")) {
                         logWindow.cleanLog();
                         return;
+                    } else if (cmd.contains("java21")) {
+                        shellUtil.append("cd " + javaDir);
+                        if (!new File(javaDir, "jre21").exists() && !new File(javaDir, "jre17_").exists()) {
+                            shellUtil.append("cp " + new File(new File(FCLPath.SHARED_COMMON_DIR).getParentFile(), "jre21.zip").getAbsolutePath() + " ./");
+                            shellUtil.append("unzip jre21.zip");
+                        }
+                        shellUtil.append("mv jre17 jre17_");
+                        shellUtil.append("mv jre21 jre17");
+                        return;
+                    } else if (cmd.contains("java17")) {
+                        shellUtil.append("cd " + javaDir);
+                        shellUtil.append("mv jre17 jre21");
+                        shellUtil.append("mv jre17_ jre17");
+                        return;
                     }
                     shellUtil.append(cmd);
                 }