Top 40 Most Asked Weblogic Interview Questions and Answers (最常问的 40 个 Weblogic 面试题及答案)

1) What is the WebLogic server, and what are its main usages? (什么是 WebLogic 服务器，它的主要用途是什么？)

WebLogic Server is a Java-based Java EE application server currently developed and managed by Oracle Corporation. That's why it is also called Oracle WebLogic Server. The Oracle organization acquired WebLogic Server when it purchased BEA Systems in 2008. The Oracle WebLogic Server is a unified and extensible platform for developing, deploying, and running enterprise applications, such as Java, on-premises, and in the cloud. (WebLogic Server 是一款基于 Java 的 Java EE 应用服务器，目前由 Oracle 公司开发和管理。因此，它也被称为 Oracle WebLogic Server。Oracle 公司在 2008 年收购 BEA Systems 时获得了 WebLogic Server。Oracle WebLogic Server 是一个统一且可扩展的平台，用于在本地和云中开发、部署和运行企业应用程序，例如 Java。)

It can host Java-based applications. It provides a robust, mature, and scalable implementation of Java Enterprise Edition (EE) and Jakarta EE. Web applications and Enterprise applications that are developed can be deployed in a WebLogic server to serve the business logic. In Layman's words, we can say that, with a WebLogic server, we can easily deploy, distribute, and run Java-based applications. (它可以托管基于 Java 的应用程序。它提供了 Java Enterprise Edition (EE) 和 Jakarta EE 的强大、成熟且可扩展的实现。已开发的 Web 应用程序和企业应用程序可以部署在 WebLogic 服务器上以提供业务逻辑。通俗地说，有了 WebLogic 服务器，我们可以轻松地部署、分发和运行基于 Java 的应用程序。)

2) What do you understand by deployment descriptors? (您如何理解部署描述符？)

In Oracle WebLogic Server, the deployment descriptors are associated with almost all the modules and applications. We can see the deployment descriptors in the form of XML documents. They are mainly used to describe the contents that are part of the directory or the jar file. J2EE specifications usually define the standard and the deployment descriptors that are portable for J2EE applications and modules. (在 Oracle WebLogic Server 中，部署描述符与几乎所有模块和应用程序相关联。我们可以看到 XML 文档形式的部署描述符。它们主要用于描述目录或 jar 文件中的内容。J2EE 规范通常定义了 J2EE 应用程序和模块的标准以及可移植的部署描述符。)

3) What are the different versions of the WebLogic Server? (WebLogic Server 有哪些不同的版本？)

The following is the list of different versions of the WebLogic Server (以下是 WebLogic Server 不同版本的列表)

4) Is Oracle WebLogic Server supported on Kubernetes? (Oracle WebLogic Server 是否支持 Kubernetes？)

The Oracle WebLogic Server is fully supported on Kubernetes. It enables users to migrate and efficiently build modern container apps with comprehensive Java services. It provides WebLogic Kubernetes ToolKit, which is a complete set of open-source tools that simplify running on Kubernetes, on-premises, or in the cloud. (Oracle WebLogic Server 完全支持 Kubernetes。它使用户能够迁移并高效地构建具有综合 Java 服务的现代容器应用程序。它提供了 WebLogic Kubernetes ToolKit，这是一套完整的开源工具，可简化在 Kubernetes、本地或云上运行。)

5) What are the core components of the Oracle WebLogic Server? (Oracle WebLogic Server 的核心组件有哪些？)

Following is the list of the core components of the Oracle WebLogic Server (以下是 Oracle WebLogic Server 的核心组件列表)

• 域
• Node Manager (节点管理器)
• Admin server (管理服务器)
• Managed server (托管服务器)
• WebLogic server cluster (WebLogic 服务器集群)
• Enterprise Grid Messaging (企业网格消息传递)
• JMS Messaging Standard (JMS 消息传递标准)
• JRockit
• Oracle Coherence (Oracle Coherence)
• Oracle TopLink (Oracle TopLink)
• Oracle WebLogic Server Web Services (Oracle WebLogic Server Web 服务)
• Tuxedo

6) What is a domain in an Oracle WebLogic server? (在 Oracle WebLogic 服务器中，什么是域？)

In the Oracle WebLogic server, domains are the logical set of resources that individually constitutes a single unit. In other words, domains are the logically related groups of Oracle WebLogic Server resources that are managed as a single unit. (在 Oracle WebLogic 服务器中，域是资源的逻辑集合，每个资源单独构成一个单元。换句话说，域是逻辑上相关的 Oracle WebLogic Server 资源组，它们作为一个单元进行管理。)

A domain provides one point of administration. It contains a special Oracle WebLogic server instance known as Administration Server, which can be used to configure and manage all resources in that specific domain. A domain can logically separate development, test, production applications, and organizational divisions. (域提供了一个管理点。它包含一个特殊的 Oracle WebLogic 服务器实例，称为管理服务器，可用于配置和管理该特定域中的所有资源。域可以逻辑上分离开发、测试、生产应用程序和组织部门。)

7) What do you understand by a Server? (您如何理解服务器？)

Oracle WebLogic Server is an application server. It is a unified and extensible platform for developing and deploying multitier distributed enterprise applications and running enterprise applications, such as Java, for on-premises and in the cloud. (Oracle WebLogic Server 是一款应用服务器。它是一个统一且可扩展的平台，用于开发和部署多层分布式企业应用程序，并在本地和云中运行企业应用程序，例如 Java。)

WebLogic Server provides a robust, mature, and scalable implementation of Java Enterprise Edition (EE) and Jakarta EE. (WebLogic Server 提供了 Java Enterprise Edition (EE) 和 Jakarta EE 的强大、成熟且可扩展的实现。)

The WebLogic Server has the following properties (WebLogic Server 具有以下特性)

• It is multithreaded. (它是多线程的。)
• It runs on a designated Oracle WebLogic Server machine. (它运行在指定的 Oracle WebLogic Server 机器上。)
• It has a dedicated amount of RAM for processing. (它有专门的 RAM 用于处理。)

There are mainly two types of Oracle WebLogic Servers (Oracle WebLogic Server 主要有两种类型)

1. Administration or Admin Server (管理服务器或 Admin Server)
2. Managed Server (托管服务器)

8) What do you understand by the Admin Server in Oracle WebLogic Servers? (您如何理解 Oracle WebLogic 服务器中的管理服务器？)

The Administration Server or Admin Server is a certain category of Oracle WebLogic Servers. It provides a central point for managing a WebLogic Server domain. Except for this type of server, all other WebLogic Server instances in a domain are called Managed Servers. As the Admin Server is the central domain configuration interface, it is used to create, delete and configure the resources of a domain like managed server, machine, cluster, data source, work managers, etc. (管理服务器或 Admin Server 是一类 Oracle WebLogic 服务器。它提供了一个管理 WebLogic Server 域的中心点。除了这种类型的服务器，域中的所有其他 WebLogic Server 实例都称为托管服务器。由于管理服务器是中央域配置接口，因此它用于创建、删除和配置域的资源，如托管服务器、机器、集群、数据源、工作管理器等。)

If a domain has only a single WebLogic Server instance, it works as both the Administration Server and the Managed Server. (如果一个域只有一个 WebLogic Server 实例，它将同时作为管理服务器和托管服务器。)

9) What is the Managed Server in Oracle WebLogic Servers? (Oracle WebLogic 服务器中的托管服务器是什么？)

The Managed Server is an instance of the WebLogic server that runs on JVM and has its configuration. We deploy the java components such as Web Applications, EJB Applications, JMS Applications, and Web services in the managed server. The managed server contacts the administration server for configuration information. It runs the business application in a production environment. It does not depend on any other managed servers in a domain unless they are not in a cluster. We can have many managed servers in a domain. Generally, a single domain can have zero to N Managed Server. (托管服务器是 WebLogic 服务器的一个实例，它运行在 JVM 上并具有自己的配置。我们将 Web 应用程序、EJB 应用程序、JMS 应用程序和 Web 服务等 Java 组件部署在托管服务器中。托管服务器会联系管理服务器以获取配置信息。它在生产环境中运行业务应用程序。除非它们不在集群中，否则它不依赖于域中的任何其他托管服务器。我们可以在一个域中拥有许多托管服务器。通常，单个域可以拥有零到 N 个托管服务器。)

Server instances other than the Administration Server are called Managed Servers in a domain. The Managed Servers in a domain can start-up independently of the Administration Server if the Administration Server is unavailable. We can configure two or more Managed Servers as a WebLogic Server cluster to increase the application scalability and availability. (管理服务器以外的服务器实例在域中称为托管服务器。如果管理服务器不可用，域中的托管服务器可以独立于管理服务器启动。我们可以将两个或多个托管服务器配置为 WebLogic Server 集群，以提高应用程序的可伸缩性和可用性。)

10) What do you understand by web.xml in the WebLogic server? (您如何理解 WebLogic 服务器中的 web.xml？)

The web.xml is an XML document mainly used for application purposes. It is very useful and helps list out the J2EE components and configuration of the application in J2EE modules format. (web.xml 是一个主要用于应用程序目的的 XML 文档。它非常有用，有助于以 J2EE 模块格式列出应用程序的 J2EE 组件和配置。)

11) Is WebLogic Server an Application Server or a Web Server? (WebLogic Server 是应用服务器还是 Web 服务器？)

The WebLogic Server is an application server. It is a platform used to develop and deploy multitier distributed enterprise applications. (WebLogic Server 是一款应用服务器。它是一个用于开发和部署多层分布式企业应用程序的平台。)

Some important features of WebLogic Server (WebLogic Server 的一些重要特性)

• The WebLogic Server is operated in the middle tier of a multitier or n-tier architecture. (WebLogic Server 在多层或 n 层体系结构的中间层运行。)
• Due to its multitier architecture, we can choose the best location for each software component, which can help develop applications faster, ease deployment and administration, and provide greater control over performance, utilization, security, scalability, and reliability. (由于其多层体系结构，我们可以为每个软件组件选择最佳位置，这有助于更快地开发应用程序，简化部署和管理，并提供对性能、利用率、安全、可伸缩性和可靠性的更高控制。)
• It centralizes application services such as Web server functionality and business components and is used to access backend enterprise systems. (它集中了 Web 服务器功能和业务组件等应用程序服务，并用于访问后端企业系统。)
• It uses caching and connection pooling technologies to improve resource use and application performance. (它使用缓存和连接池技术来提高资源利用率和应用程序性能。)
• It also provides enterprise-level security and powerful administration facilities. (它还提供企业级安全和强大的管理功能。)
• The WebLogic server can host both Web applications and Enterprise applications (such as EJBs). (WebLogic 服务器可以托管 Web 应用程序和企业应用程序（如 EJB）。)
• It implements J2EE, the Java Enterprise standard. (它实现了 Java Enterprise 标准 J2EE。)

12) What are the different thread states in a WebLogic server? (WebLogic 服务器中有哪些不同的线程状态？)

Following is a list of several thread states used in a WebLogic server (以下是 WebLogic 服务器中使用的一些线程状态列表)

• ACTIVE (活动)
• IDLE
• STUCK (卡住)
• HOGGER (占用)
• STANDBY (待命)

13) What methods can be used to provide user credentials for starting the server? (可以使用哪些方法为启动服务器提供用户凭据？)

When the domain is created, the wizard for setting configuration asks for the details, like user name, password, etc., from the user who is logging in for the first time as the administrator. If you have created the domain in development mode, the configuration wizard saves the encrypted password and the username inside the identity file. When the system is booting, this file is available for reference so that in the absence of this file, the system can prompt the user so that it can enter the credentials. A new boot named "identity file" can be created if you want to change the user credentials or if you have the requirement of creating a domain in production mode. (创建域时，设置配置的向导会询问第一次以管理员身份登录的用户有关用户名、密码等详细信息。如果您在开发模式下创建了域，配置向导会将加密的密码和用户名保存在身份文件中。系统启动时，此文件可供参考，因此在缺少此文件的情况下，系统可以提示用户输入凭据。如果您想更改用户凭据或有在生产模式下创建域的要求，可以创建一个名为“身份文件”的新启动。)

14) What would happen if the Administration Server fails? (如果管理服务器失败会怎样？)

If the Administration Server fails for a domain, it does not affect the operation of Managed Servers in the domain. If an Administration Server for a domain becomes unavailable while the server instances it manages (clustered or otherwise) are up and running, those Managed Servers continue to run. If the domain contains clustered server instances, the load balancing and failover capabilities supported by the domain configuration remain available, even if the Administration Server fails. In this case, if the Administration Server stops running while the Managed Servers in the domain continue to run, then each Managed Server periodically attempts to reconnect to the Administration Server. (如果域的管理服务器失败，不会影响托管服务器在域中的运行。如果域的管理服务器在它管理的服务器实例（集群的或其他）正在运行时变得不可用，那些托管服务器将继续运行。如果域包含集群服务器实例，即使管理服务器失败，由域配置支持的负载均衡和故障转移功能仍然可用。在这种情况下，如果管理服务器停止运行时，域中的托管服务器继续运行，那么每个托管服务器会定期尝试重新连接到管理服务器。)

If the system faces any hardware or software failure on its host machine, and if the Administration Server fails, then the other server instances on the same machine may be similarly affected. But, if the Administration Server fails, it does not interrupt the operation of Managed Servers in the domain. You can start a Managed Server even if the Administration Server is not running. In this case, the Managed Server uses a local copy of its configuration files for its starting configuration and then periodically attempts to connect with the Administration Server. In this case, if the connection doesn't occur, it synchronizes its configuration state with the Administration Server. (如果系统在其主机上遇到任何硬件或软件故障，并且管理服务器失败，那么同一台机器上的其他服务器实例也可能受到类似影响。但是，管理服务器的失败不会中断域中托管服务器的运行。即使管理服务器未运行，您也可以启动托管服务器。在这种情况下，托管服务器使用其配置文件的本地副本作为其启动配置，然后定期尝试与管理服务器连接。在这种情况下，如果连接不成功，它会与管理服务器同步其配置状态。)

14) What are the different supported installation modes available for WebLogic Server? (WebLogic Server 有哪些不同的支持的安装模式？)

Following are the three supported installation modes available for WebLogic Server (以下是 WebLogic Server 的三种支持的安装模式)

• Console mode: The console mode is an installation mode based on interactive text messages. (控制台模式：控制台模式是一种基于交互式文本消息的安装模式。)
• Graphical mode: The graphical mode is an installation mode based on the interactive GUI. (图形模式：图形模式是一种基于交互式 GUI 的安装模式。)
• Silent mode: The silent mode is an installation mode based on the properties file that is provided with it, which doesn't require any interaction. (静默模式：静默模式是一种基于提供的属性文件的安装模式，不需要任何交互。)

16) What is the use of HTTP? (HTTP 的用途是什么？)

HTTP is a protocol that enables the communication between the WebLogic server and processes. (HTTP 是一种允许 WebLogic 服务器和进程之间通信的协议。)

17) What are the key differences between the stage and the non-stage deployments in Weblogic Server? (Weblogic 服务器中阶段部署和非阶段部署之间的主要区别是什么？)

The stage deployment is a process where the Admin receives a copy which is later distributed amongst the available instances. On the other hand, the Non-Stage deployment provides a restriction that each instance needs to contact the source for the necessary deployments. (阶段部署是一个过程，其中管理员接收一个副本，然后该副本在可用实例之间分发。另一方面，非阶段部署提供了一个限制，即每个实例都需要联系源以进行必要的部署。)

18) How many ways can we provide credentials to start the WebLogic server? (我们可以通过多少种方式为启动 WebLogic 服务器提供凭据？)

There are three ways to provide credentials to start the WebLogic server (有三种方式可以为启动 WebLogic 服务器提供凭据)

• Command-line: When a domain is created in the command-line, details like the username and password are prompted via a wizard to configure. (命令行：在命令行创建域时，会通过向导提示输入用户名和密码等详细信息进行配置。)
• Via boot.properties file: It specifies that if a domain is already created in Development mode, the encrypted credentials are stored in an identity file. We can enter the password if this identity file isn't available during the boot-up process. (通过 boot.properties 文件：它指定如果域已在开发模式下创建，加密的凭据将存储在身份文件中。如果此身份文件在启动过程中不可用，我们可以输入密码。)
• Java Option: In this option, on a new boot, we can create a new identity file with the credentials or if there is a requirement to create a new domain in Production mode. (Java 选项：在此选项中，在新启动时，我们可以使用凭据创建一个新的身份文件，或者如果需要，可以在生产模式下创建一个新域。)

19) What is the default port of the Weblogic admin server? (Weblogic 管理服务器的默认端口是什么？)

The default port of the WebLogic Admin server is 7001. It is 7002 for SSL. (WebLogic 管理服务器的默认端口是 7001。SSL 端口是 7002。)

20) How can we start and stop a WebLogic server? (我们如何启动和停止 WebLogic 服务器？)

There are several ways to start and stop a WebLogic server. Some of them are as follows (有几种方法可以启动和停止 WebLogic 服务器。其中一些如下：)

• By using the command java WebLogic.server (使用命令 java WebLogic.server)
• By using Windows services (使用 Windows 服务)
• By using scripts (使用脚本)
• WLST with or without Node Managers (使用或不使用节点管理器的 WLST)

21) What is the auto-deployment feature in the WebLogic server? How can you turn off this feature? (WebLogic 服务器中的自动部署功能是什么？如何关闭此功能？)

The auto-deployment mode or auto-deployment feature of the WebLogic server works for the development mode. Here it checks every 3 seconds to see if any new applications are available or any new changes are available for the existing applications and deploy them. (WebLogic 服务器的自动部署模式或自动部署功能适用于开发模式。它每 3 秒检查一次是否有新应用程序可用或现有应用程序是否有新更改，并进行部署。)

Following are some available options that can be used to disable this automatic deployment feature in the WebLogic server (以下是一些可用于禁用 WebLogic 服务器中此自动部署功能的选项)

• Select the Production mode checkbox from the Administration Console for the necessary domain. (从管理控制台中为必要的域选择“生产模式”复选框。)
• On CLI, use option -Dweblogic.ProductionModeEnabled=true when starting the respective domain's Administration Server. (在 CLI 上，在启动相应域的管理服务器时，使用选项 -Dweblogic.ProductionModeEnabled=true。)

22) How can you set a CLASSPATH in a WebLogic server? (如何在 WebLogic 服务器中设置 CLASSPATH？)

We can use the script files from WebLogic to set a CLASSPATH in a WebLogic server. These files should be used based on the OS type (Windows or Linux) (我们可以使用 WebLogic 的脚本文件在 WebLogic 服务器中设置 CLASSPATH。应根据操作系统类型（Windows 或 Linux）使用这些文件)

• WL_HOME/server/bin/setWLSEnv.cmd for Windows (Windows 系统使用 WL_HOME/server/bin/setWLSEnv.cmd)
• WL_HOME/server/bin/setWLSEnv.sh for Linux (Linux 系统使用 WL_HOME/server/bin/setWLSEnv.sh)

23) What is the process to access the admin console of the WebLogic server? (访问 WebLogic 服务器管理控制台的过程是什么？)

We can access the admin console of the WebLogic server by entering the administration machine name and port in the browser's navigation bar. After that, we have to ask for the login credentials. (我们可以通过在浏览器的导航栏中输入管理机器名称和端口来访问 WebLogic 服务器的管理控制台。之后，我们需要输入登录凭据。)

24) How can you see the version of the WebLogic server that you are using? (如何查看您正在使用的 WebLogic 服务器的版本？)

Follow the steps given to see the version of the WebLogic server that you are using (按照以下步骤查看您正在使用的 WebLogic 服务器的版本)

• First, go to the WebLogic Server console (首先，转到 WebLogic 服务器控制台)
• Click on the Environment -> Servers -> Monitoring -> WebLogic Version field (点击“环境”->“服务器”->“监控”->“WebLogic 版本”字段)
• See there to check the version of the WebLogic server that you are using. (在此处查看您正在使用的 WebLogic 服务器的版本。)

25) What are the different ways to configure a Managed server in the WebLogic server? (配置 WebLogic 服务器中的托管服务器有哪些不同方法？)

There are three ways to configure a Managed server in the WebLogic server (有三种方法可以在 WebLogic 服务器中配置托管服务器)

• WebLogic scripting tool (WebLogic 脚本工具)
• Administration Console (管理控制台)
• Domain Configuration wizard (域配置向导)

26) What are the main capabilities of a WebLogic server? (WebLogic 服务器的主要功能是什么？)

Following is the list of the main capabilities of a WebLogic server (以下是 WebLogic 服务器的主要功能列表)

• To make changes in dynamic configuration. (进行动态配置更改。)
• To redeploy the production application. (重新部署生产应用程序。)
• For Rolling upgrades. (用于滚动升级。)

27) What is the main functionality of IIOP? (IIOP 的主要功能是什么？)

IIOP is a protocol that enables communication between the WebLogic server and object request broker. (IIOP 是一种允许 WebLogic 服务器和对象请求代理之间通信的协议。)

28) What do you understand by BSU in the WebLogic server? (您如何理解 WebLogic 服务器中的 BSU？)

BSU stands for BEA Smart Update utility or WebLogic Smart Update. It is a utility available to update or apply patches on WebLogic Servers. You can see it under the following folder (WL_HOME/utils/bsu). (BSU 是 BEA Smart Update 实用程序或 WebLogic Smart Update 的缩写。它是一个可用于更新或应用 WebLogic 服务器补丁的实用程序。您可以在以下文件夹中找到它（WL_HOME/utils/bsu）。)

29) What is the difference between Weblogic Development and Production Mode? (Weblogic 开发模式和生产模式之间有什么区别？)

Following is a list of some differences between Weblogic Development Mode and Production Mode (以下是 Weblogic 开发模式和生产模式之间的一些差异列表)

30) What is the main functionality of T3 associated with the WebLogic server? (与 WebLogic 服务器关联的 T3 的主要功能是什么？)

The main functionality of T3 associated with the WebLogic server is providing a framework or overall structure for the messages that can support the enhancements. T3 performs serialization of java object and also predation of RMI. It is considered a superset associated with java objects. The enhancements include product tunneling, working in the context associated with WebLogic server clusters, and object replacement. (与 WebLogic 服务器关联的 T3 的主要功能是提供消息的框架或整体结构，以支持增强功能。T3 执行 Java 对象的序列化以及 RMI 的预测。它被认为是 Java 对象的超集。增强功能包括产品隧道，在与 WebLogic 服务器集群相关的上下文中工作，以及对象替换。)

31) How can you set a classpath in the WebLogic server? (如何在 WebLogic 服务器中设置类路径？)

We can set a classpath in the WebLogic server by making use of the following script (我们可以通过使用以下脚本在 WebLogic 服务器中设置类路径)

32) What steps are involved in creating Pooling within the Tomcat server? (在 Tomcat 服务器中创建连接池涉及哪些步骤？)

There are mainly two steps involved in the creation of Pooling within the Tomcat server (在 Tomcat 服务器中创建连接池主要涉及两个步骤)

• In the first step, we have to download three jar files: the commons-dbcp-1.2 jar, commons-pool-1.3.jar, and commons-collections-3.1 jar. (第一步，我们需要下载三个 jar 文件：commons-dbcp-1.2 jar、commons-pool-1.3.jar 和 commons-collections-3.1 jar。)
• In the next step, we have to enter the server.xml of the tomcat factory. (下一步，我们需要输入 Tomcat 工厂的 server.xml。)

33) How do stubs function inside the WebLogic server cluster at the time of failure? (故障发生时，存根在 WebLogic 服务器集群中的功能如何？)

Stubs are used to remove the failed instance from the list whenever a failure occurs. It generally uses DNS to find the running server and obtain the list of the instances currently available with the application. A list of the instances available with the server inside the cluster gets refreshment periodically and allows for acquiring advantages associated with new servers. As the server gets added to the cluster, the advantages are achieved. (每当发生故障时，存根都用于从列表中删除失败的实例。它通常使用 DNS 来查找正在运行的服务器并获取当前应用程序可用的实例列表。集群中服务器可用的实例列表会定期刷新，并允许获得与新服务器相关的优势。随着服务器添加到集群中，优势也随之实现。)

34) What is the key difference between server crash and server hang? (服务器崩溃和服务器挂起之间的关键区别是什么？)

The main difference between server crash and server hang is that in a server crash, there is no existence of the Java process. On the other hand, in the server hang, the Java process stops responding. (服务器崩溃和服务器挂起之间的主要区别在于，在服务器崩溃时，Java 进程不存在。另一方面，在服务器挂起时，Java 进程停止响应。)

35) How can you solve the server hang problem? (如何解决服务器挂起问题？)

To solve the server hang problem, we have to check the Java WebLogic.Admin PING whether we get a normal and positive response. We can find out the root cause for hanging from this file by rectifying the errors that are identified in this file. (要解决服务器挂起问题，我们需要检查 Java WebLogic.Admin PING 是否得到正常且积极的响应。通过纠正此文件中识别出的错误，我们可以找出挂起问题的根本原因。)

36) What are the main reasons for server hang? (服务器挂起的主要原因是什么？)

The main reasons for server hang are memory leak, deadlock, and a long return time. (服务器挂起的主要原因是内存泄漏、死锁和长时间的返回时间。)

37) What are the main causes of a server crash? (服务器崩溃的主要原因是什么？)

The main causes of server crashes are the native IO, JVM, supported configuration, JDBC driver issues, and SSL native libraries. (服务器崩溃的主要原因包括本地 IO、JVM、支持的配置、JDBC 驱动程序问题和 SSL 本地库。)

38) What is the boot.properties file in the WebLogic server? Why is it important? (WebLogic 服务器中的 boot.properties 文件是什么？它为什么重要？)

The boot.properties file is available under the domain/servers/<YOUR_SERVER_NAME>/security folder. This file can be used by both the Administration server and/or the Managed server to get the login credentials. (boot.properties 文件位于 domain/servers//security 文件夹下。管理服务器和/或托管服务器都可以使用此文件来获取登录凭据。)

39) How can you solve the problem of a server crash? (如何解决服务器崩溃问题？)

We can solve the problem of server crashes by focusing on the following things (我们可以通过关注以下几点来解决服务器崩溃问题)

A crash associated with JVM generates the hs_err_pid file. We have to refer to this file to find the root cause of such a crash. If the native IO is the origin of the thread, we need to disable it. If the origin of the problem is from the driver, we need to contact the driver team. (与 JVM 相关的崩溃会生成 hs_err_pid 文件。我们必须参考此文件来查找此类崩溃的根本原因。如果本地 IO 是线程的源头，我们需要禁用它。如果问题源于驱动程序，我们需要联系驱动程序团队。)

40) What are the reasons behind the OUT OF MEMORY condition? (内存不足的原因是什么？)

Following are the various reasons behind the OUT OF MEMORY condition (内存不足的各种原因如下)

• If the heap size is insufficient as compared to the extra load. (与额外负载相比，堆内存不足。)
• If the memory leak occurs inside the application code. (如果应用程序代码中发生内存泄漏。)
• Placing the objects takes a longer period, like that of HTTP sessions. (放置对象需要更长的时间，例如 HTTP 会话。)
• The prevention of occurrence of full GC because of JVM bug. (由于 JVM 错误而阻止完全 GC 的发生。)