webView.clearCache(true);
webView.clearHistory();

if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
	CookieSyncManager cookieSyncMngr=CookieSyncManager.createInstance(MainActivity.this);
	cookieSyncMngr.startSync();
	CookieManager cookieManager=CookieManager.getInstance();
	cookieManager.removeAllCookie();
	cookieManager.removeSessionCookie();
	cookieSyncMngr.stopSync();
	cookieSyncMngr.sync();
}else {
	CookieManager cookieManager = CookieManager.getInstance();
	cookieManager.removeAllCookies(new ValueCallback() {
		@Override
		public void onReceiveValue(Boolean value) {
		Log.d("onReceiveValue", value.toString());
		}
	});
	cookieManager.getInstance().flush();
}