Android SQLiteException syntax error code 1 -

i made database in application, code giving error syntax (code 1) table exception. read questions exception, did said. still doesn't work. couldn't find problem is. there 1 can me?

my code here :

public class notesdatabaseadapter {      public static final string key_name = "name";     public static final string key_image = "icon";     public static final string key_date_time = "when";     public static final string key_rowid = "_id";     private static final string tag = "notesdatabaseadapter";     private databasehelper mdbhelper;     private sqlitedatabase mdatabase;     private static final string database_table = "downloads";      /**      * khởi tạo cơ sở dữ liệu      */     private static final string database_name = "blogradio.db";     private static final int database_version = 1;     private static final string create_download_table = "create table "             + database_table + "(" + key_rowid             + " integer primary key autoincrement, " + key_name             + " text not null, " + key_image + " text not null, "             + key_date_time + " text not null);";      private final context mctx;      private static class databasehelper extends sqliteopenhelper {          databasehelper(context context) {             super(context, database_name, null, database_version);         }          @override         public void oncreate(sqlitedatabase db) {             log.i("", "abc " + create_download_table);             db.execsql(create_download_table);         }          @override         public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {             log.w(tag, "upgrading database version " + oldversion + " "                     + newversion + ", destroy old data");             db.execsql("drop table if exists " + database_table);             oncreate(db);         }     }      /**      * constructor - takes context allow database      * opened/created      *       * @param ctx      *            context within work      */     public notesdatabaseadapter(context ctx) {         this.mctx = ctx;     }      /**      * open notes database. if cannot opened, try create new      * instance of database. if cannot created, throw exception      * signal failure      *       * @return (self reference, allowing chained in      *         initialization call)      * @throws sqlexception      *             if database neither opened or created      */     public notesdatabaseadapter open() throws sqlexception {         mdbhelper = new databasehelper(mctx);         mdatabase = mdbhelper.getwritabledatabase();         return this;     }      public void close() {         mdbhelper.close();     }      /**      * create new note using title , body provided. if note      * created return new rowid note, otherwise return      * -1 indicate failure.      *       * @param title      *            title of note      * @param body      *            body of note      * @return rowid or -1 if failed      */      public long createnote(itemdownload item) {         contentvalues initialvalues = new contentvalues();         initialvalues.put(key_name, item.getname());         initialvalues.put(key_image, item.geticon());         initialvalues.put(key_date_time, item.getwhen());         return mdatabase.insert(database_table, null, initialvalues);     }      /**      * delete note given rowid      *       * @param rowid      *            id of note delete      * @return true if deleted, false otherwise      */     public boolean deletenote(long rowid) {         return mdatabase.delete(database_table, key_rowid + "=" + rowid, null) > 0;     }      /**      * return cursor on list of notes in database      *       * @return cursor on notes      */     // lây toàn bộ các ghi chú để hiển thị lên listview     public cursor fetchallnotes() {          return mdatabase.query(database_table, new string[] { key_rowid,                 key_name, key_image, key_date_time }, null, null, null, null,                 null);     }      /**      * return cursor positioned @ note matches given rowid      *       * @param rowid      *            id of note retrieve      * @return cursor positioned matching note, if found      * @throws sqlexception      *             if note not found/retrieved      */     public cursor fetchnote(long rowid) throws sqlexception {          cursor mcursor =          mdatabase.query(true, database_table, new string[] { key_rowid,                 key_name, key_image, key_date_time }, key_rowid + "=" + rowid,                 null, null, null, null, null);         if (mcursor != null) {             mcursor.movetofirst();         }         return mcursor;      }      /**      * update note using details provided. note updated      * specified using rowid, , altered use title , body      * values passed in      *       * @param rowid      *            id of note update      * @param title      *            value set note title      * @param body      *            value set note body      * @return true if note updated, false otherwise      */     public boolean updatenote(long rowid, itemdownload item) {         contentvalues args = new contentvalues();         args.put(key_name, item.getname());         args.put(key_image, item.geticon());          args.put(key_date_time, item.getwhen());          return mdatabase.update(database_table, args, key_rowid + "=" + rowid,                 null) > 0;     } } 

mainactivity :

public class requestclass extends activity implements onclicklistener {     button start, stop, startactivity;     int btnstart, btnstop;     public static final string state = "start";     private intent intent;     notesdatabaseadapter db;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.request_layout);         db = new notesdatabaseadapter(requestclass.this);         db.open();         start = (button) findviewbyid(r.id.btnstartservice);         stop = (button) findviewbyid(r.id.btnstopservice);         startactivity = (button) findviewbyid(r.id.btnstartactivity);         start.setonclicklistener(this);         stop.setonclicklistener(this);         startactivity.setonclicklistener(this);      }      @override     public void onclick(view view) {         switch (view.getid()) {         case r.id.btnstartservice:             intent = new intent(this, serviceclass.class);             intent.putextra(state, "http://media3.nhacvietplus.com.vn/upload/cms/nam_2015/thang_5/ngay_7/images/blog-radio389-5.jpg"); //          itemdownload item = new itemdownload("blogradio", "xxx", "http://media3.nhacvietplus.com.vn/upload/cms/nam_2015/thang_5/ngay_7/images/blog-radio389-5.jpg"); //          db.createnote(item); //          db.close();             startservice(intent);              break;         case r.id.btnstopservice:             stopservice(intent);             break;         case r.id.btnstartactivity:             intent = new intent(requestclass.this, responseclass.class);             startactivity(i);             break;         }     }      @override     protected void onresume() {         super.onresume();     }      @override     protected void onpause() {         super.onpause();     }      @override     protected void ondestroy() {         super.ondestroy();     } } 

logcat :

05-14 14:08:41.152: e/sqlitelog(1979): (1) near "when": syntax error 05-14 14:08:41.152: d/androidruntime(1979): shutting down vm 05-14 14:08:41.152: w/dalvikvm(1979): threadid=1: thread exiting uncaught exception (group=0xa61fe908) 05-14 14:08:41.156: e/androidruntime(1979): fatal exception: main 05-14 14:08:41.156: e/androidruntime(1979): java.lang.runtimeexception: unable start activity componentinfo{android.tadev.demodownloadservice/android.tadev.downloadservice.temp.requestclass}: android.database.sqlite.sqliteexception: near "when": syntax error (code 1): , while compiling: create table downloads(_id integer primary key autoincrement, name text not null, icon text not null, when text not null); 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2180) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.activitythread.handlelaunchactivity(activitythread.java:2230) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.activitythread.access$600(activitythread.java:141) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.activitythread$h.handlemessage(activitythread.java:1234) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.os.handler.dispatchmessage(handler.java:99) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.os.looper.loop(looper.java:137) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.activitythread.main(activitythread.java:5041) 05-14 14:08:41.156: e/androidruntime(1979):     @ java.lang.reflect.method.invokenative(native method) 05-14 14:08:41.156: e/androidruntime(1979):     @ java.lang.reflect.method.invoke(method.java:511) 05-14 14:08:41.156: e/androidruntime(1979):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:793) 05-14 14:08:41.156: e/androidruntime(1979):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:560) 05-14 14:08:41.156: e/androidruntime(1979):     @ dalvik.system.nativestart.main(native method) 05-14 14:08:41.156: e/androidruntime(1979): caused by: android.database.sqlite.sqliteexception: near "when": syntax error (code 1): , while compiling: create table downloads(_id integer primary key autoincrement, name text not null, icon text not null, when text not null); 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqliteconnection.nativepreparestatement(native method) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqliteconnection.acquirepreparedstatement(sqliteconnection.java:882) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqliteconnection.prepare(sqliteconnection.java:493) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqlitesession.prepare(sqlitesession.java:588) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqliteprogram.<init>(sqliteprogram.java:58) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqlitestatement.<init>(sqlitestatement.java:31) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqlitedatabase.executesql(sqlitedatabase.java:1663) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqlitedatabase.execsql(sqlitedatabase.java:1594) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.tadev.downloadservice.temp.notesdatabaseadapter$databasehelper.oncreate(notesdatabaseadapter.java:44) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqliteopenhelper.getdatabaselocked(sqliteopenhelper.java:252) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.database.sqlite.sqliteopenhelper.getwritabledatabase(sqliteopenhelper.java:164) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.tadev.downloadservice.temp.notesdatabaseadapter.open(notesdatabaseadapter.java:79) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.tadev.downloadservice.temp.requestclass.oncreate(requestclass.java:23) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.activity.performcreate(activity.java:5104) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1080) 05-14 14:08:41.156: e/androidruntime(1979):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2144) 05-14 14:08:41.156: e/androidruntime(1979):     ... 11 more 

you can't call column "when", since keyword in sqlite