OAuth 2.0 playground（playground）是WSO2 Identity Server（WSO2-IS）的OAuth客户端示例应用程序。我可以用WSO2-IS v4.0.0m3执行playground，但它与WSO2-IS v4.0.0m9（如下所示的异常消息）一起崩溃。操场已经更新为IS v4.0.0m9？如何更新/修复游乐场样本？
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java.lang.NullPointerException
org.wso2.carbon.identity.oauth.ui.client.OAuth2ServiceClient._validateClient(OAuth2ServiceClient.java:113)
org.wso2.carbon.identity.oauth.ui.client.OAuth2ServiceClient.validateClient(OAuth2ServiceClient.java:107)
org.wso2.carbon.identity.oauth.ui.endpoints.authz.OAuth2AuthzEndpoint.validateClient(OAuth2AuthzEndpoint.java:171)
org.wso2.carbon.identity.oauth.ui.endpoints.authz.OAuth2AuthzEndpoint.handleOAuthAuthorizationRequest(OAuth2AuthzEndpoint.java:106)
org.wso2.carbon.identity.oauth.ui.endpoints.authz.OAuth2AuthzEndpoint.service(OAuth2AuthzEndpoint.java:70)