324 Java interview questions for IT Enterprises

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1. 324 Java interview questions for IT Enterprises
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324 Java interview questions for IT Enterprises

 

 

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Go to Chapter 324 of the 1st Java interview questions required by IT Enterprises

Go to Chapter 324 of the 2nd Java interview questions required by IT Enterprises

 

This document describes the problems that often occur during Java interviews and provides guidance to readers to answer questions quickly and skillfully. The book is divided into 18 chapters, the content covers several things that must be known before the interview, Java program basics, symbols in the Java language, data type and type conversion, arrays and strings, process control, exception handling, and memory management., input/output stream, object-oriented, Java multithreading, package and access control, set, database, J2EE technology, XML/UML technology, Servlet/JSP technology and common machine programming and interesting questions such as thinking training. Introduction to each chapterChapter 1 The several things that must be known before an interview are repeated job interviews. Just like an invisible battle, they determine the fate of different people and different people. If you want to win in the battle, you must know yourself and know what you want to win. If you want to stand out from many competitors, you will not rely on a strong body, but on a keen mind and full preparation. Are you ready when the battle is about to begin? By studying this book, you will be fully prepared and confident. Chapter 2 Java program basics 24 the most important step to learn java well is programming on the machine. Familiarity with Java Development and running environments is the first step to become a Java programmer. By examining the basic aspects of Java programming, we can fully reflect the degree of understanding and proficiency of the interviewer in Java. In this chapter, I will explain the test points of the basic part of Java programming from multiple perspectives through real interview questions, so that the interviewer can quickly master the essentials of Java interview and improve his/her probability of success in the interview. Chapter 4 the Java symbol 49java programming language, like other programming languages, is also composed of syntax rules and semantic definitions. Syntax Rules define legal sentence structures constructed by language elements, while semantic definitions explain the meanings of these sentence patterns. We should have a deep understanding of the concepts of various knowledge points and keep in mind some java syntax, so as to achieve the purpose of learning. Chapter 5 data types and type conversion 75 data types are internal manifestations of exponential data. Java is a language that emphasizes data types. When declaring any variable, you must define the variable as a data type. Data is divided into different types based on different forms of data. Different Data Types allow different operations and different value ranges. The data types provided by Java include basic data types and composite data types. This chapter describes the basic types of data. In Java programs, there are a total of eight basic types, including four integer types, one primitive type, two floating point types, and one boolean type. In addition to these basic types, all others belong to the composite data type. Table 4.1 lists the data types in the Java language. Chapter 2 arrays and strings 97 This chapter introduces two pre-defined classes in Java: arrays and strings. They are also two types of data structures that must be processed by all programming languages. In traditional languages (such as C), arrays and strings are only a piece of continuous memory space, used to store the same type of data, and the language itself does not provide more support for it. Java designs it as an object and has more built-in methods, reducing the workload of programmers. In addition, Java will detect the subscript of the array. If there is any subscript out of bounds, it will be reported in a timely manner, avoiding a major problem plaguing C/C ++ programmers. Let's start with the array. Chapter 1 Process Control 6th what is process control? The process is the order of one thing, or the order. In program design, the process is to complete a function, and the process control is to control the order of completion of a function in the program design. A statement is a control component of a program. It has specific syntax rules and strict expressions to control the running of the program. Therefore, a statement is also a structured control structure. These control structures can be classified into three types: sequential structure, selection structure, and cyclic structure. Statements that implement these control structures can be divided into five types: expression statements, compound statements, branch statements, loop statements, and jump statements. This chapter describes these statements one by one. Chapter 5 Exception Handling and memory management 7th this problem is often encountered during actual project development. For example, a program does not produce error information during compilation, but when the program is running, some running Errors often occur, which is an exception for Java. An exception refers to an error or abnormal state that occurs when the program is running. If an exception occurs, a corresponding handling method is required. Exception Handling is an advantage of Java. In exception handling, its processing mechanism is well designed and easy to use, which not only improves the robustness of the program, it also greatly reduces the programming workload of programmers. Therefore, to successfully become a qualified Java programmer, mastering the exception handling mechanism is essential for writing large programs. Chapter 1 input/output stream 8th if an application does not have input or output, the user cannot provide the required information. Input and output are the interfaces provided by the entire application, allowing you to know what the application is intended for and what to do. For example, inputting some data on the keyboard, displaying the data on the display, and saving it into a file will involve information input/output processing. In Java, Information Input and Output (I/O) are an important part of programming languages. I/O refers to the data input and output by applications to these devices. In the program, the keyboard is used for file input, and the display is used for file output. Chapter 2 Object-Oriented Programming (OOP) is no stranger to the members of the IT field, because the first thing that comes into contact with OOP is from entering the IT field, every day, everyone is talking about oop. They need to have OOP ideas, but what is oop? What is oop? Whether I am a beginner in Java or a veteran who has been working for many years, I feel very confused about this problem and abstract it. My mind is just a vague concept, because the problem is abstracted, it is difficult to understand, so most recruitment companies use it as the evaluation standard. Therefore, how to understand OOP design ideas, inheritance and interfaces is a common test content in interviews. Chapter 1 multi-thread Java 10th so far, in traditional programming languages, most programmers are used to considering how to execute tasks sequentially from start to end, that is to say, a program has only one execution route, but many processes occur simultaneously in life. Java's "multithreading" can make up for this defect. It can run different program blocks together, make the program run more smoothly, and achieve the simultaneous processing of multiple tasks. Chapter 2 Package and access control 11th in Java, you can put classes and interfaces with similar functions and common properties into a file, which can be used to classify namespaces, you can also control access between classes. Compile and execute these files together, so that the program code is easier to maintain. At the same time, after the classes are separated, the corresponding access permissions are granted to the class usage. This chapter describes how to use packages and access control permissions. Chapter 1 class set framework 12th there are two important courses in computer science-data structures and algorithms-to show you how to accomplish common tasks. Because it is quite difficult for people to learn and understand the two, Java designers have designed a lot of methods to help programmers quickly surpass the gap, encapsulate common data structures and algorithms. These classes that process data structures and algorithms are stored in the collection library. This chapter introduces the usage of these classes. Chapter 2 database 13th This chapter describes how to use classes in the Java class library to write database applications. Databases play an important role in the program. Most practical applications use databases to store information. Databases and applications are independent of each other, databases are responsible for persistent data, and applications are responsible for business logic. To learn database programming, in addition to learning related classes such as JDBC in Java class libraries, you also need to learn the database query language-SQL, and learn this language specially designed for databases, you can write a database application in a Java program. After learning the language, you must learn the database software and perform visualized operations on the database. Large databases such as Oracle and MySQL. Chapter 2 J2EE (Java ee) and EJB 14th Technology Development 318j2ee are short for JAVA Platform Enterprise Edition (Java platform, Enterprise Edition). It contains a set of technical specifications and guidelines, including many components, it can simplify and standardize the development and deployment of application systems to improve portability, security, and reuse value. J2EE is based on Java SE, and a new class library is added for enterprise applications. Sun was initially named J2EE in its JAVA Platform Enterprise Edition and renamed Java EE 1.5 after J2EE 5.0. Java EE is the result of software technology development. Chapter 4 XML, UML, and mvc345 This chapter mainly describes the basic concepts and simple usage of XML and UML and the meaning of MVC. XML (Extensible Markup Language) is a new generation of data exchange standard released by the World Wide Web society (W3C). translating it into Chinese is "extensible markup language ". UML (Unified Modeling Language) is a modeling language and a main tool for requirement analysis and outline design. MVC (model, view, Controller) is the design mode of application development. M is the exponential data model; V is the user interface; C is the controller. Chapter 2 JSP/Servlet technology 16th in Java Development, JSP/servlet is a web layer technology, and JSP and Servlet are both sides of one, you can use a separate technology to address the demand for dynamic web page presentation, but the best way is to take the advantages of both. jsp is oriented by web page designers, servlet is guided by programmers. At present, most Java Development in China is Java Web development. clarifying their responsibilities allows two teams with different expertise to cooperate with each other, and reduce mutual restraint. Therefore, Servlet/JSP is also required in the Java programmer interview. Chapter 2 common questions on Java computers 17th the computer programming examination requires the interviewer to use a programming tool to write all the code and debug and run it according to the requirements of the questions. This is mainly to examine the examinee's proficiency in code writing and programming. It is worth noting that such interview questions require proper running, and usually require the interviewer to use the original JDK compilation method, that is, to use the doscommand prompt, rather than providing a rapid development environment such as eclipse or JBuilder. This chapter classifies frequently-encountered computer programming questions, hoping to help and inspire readers. Chapter 1 thinking and Intelligence Testing 18th this type of interview questions puts forward higher requirements for the interviewer. Questions about thinking expansion can be divided into two categories. One is thinking extended programming. First, the interviewer needs to establish a programming model and then use code programming to give answers. The other is intelligence testing, measure the test taker's knowledge about how to think and respond to the problem. No programming is required to solve the problem. 324 Java interview questions for IT Enterprises

 

 

Example

Go to Chapter 324 of the 1st Java interview questions required by IT Enterprises

Go to Chapter 324 of the 2nd Java interview questions required by IT Enterprises

 

This document describes the problems that often occur during Java interviews and provides guidance to readers to answer questions quickly and skillfully. The book is divided into 18 chapters, the content covers several things that must be known before the interview, Java program basics, symbols in the Java language, data type and type conversion, arrays and strings, process control, exception handling, and memory management., input/output stream, object-oriented, Java multithreading, package and access control, set, database, J2EE technology, XML/UML technology, Servlet/JSP technology and common machine programming and interesting questions such as thinking training. Introduction to each chapterChapter 1 The several things that must be known before an interview are repeated job interviews. Just like an invisible battle, they determine the fate of different people and different people. If you want to win in the battle, you must know yourself and know what you want to win. If you want to stand out from many competitors, you will not rely on a strong body, but on a keen mind and full preparation. Are you ready when the battle is about to begin? By studying this book, you will be fully prepared and confident. Chapter 2 Java program basics 24 the most important step to learn java well is programming on the machine. Familiarity with Java Development and running environments is the first step to become a Java programmer. By examining the basic aspects of Java programming, we can fully reflect the degree of understanding and proficiency of the interviewer in Java. In this chapter, I will explain the test points of the basic part of Java programming from multiple perspectives through real interview questions, so that the interviewer can quickly master the essentials of Java interview and improve his/her probability of success in the interview. Chapter 4 the Java symbol 49java programming language, like other programming languages, is also composed of syntax rules and semantic definitions. Syntax Rules define legal sentence structures constructed by language elements, while semantic definitions explain the meanings of these sentence patterns. We should have a deep understanding of the concepts of various knowledge points and keep in mind some java syntax, so as to achieve the purpose of learning. Chapter 5 data types and type conversion 75 data types are internal manifestations of exponential data. Java is a language that emphasizes data types. When declaring any variable, you must define the variable as a data type. Data is divided into different types based on different forms of data. Different Data Types allow different operations and different value ranges. The data types provided by Java include basic data types and composite data types. This chapter describes the basic types of data. In Java programs, there are a total of eight basic types, including four integer types, one primitive type, two floating point types, and one boolean type. In addition to these basic types, all others belong to the composite data type. Table 4.1 lists the data types in the Java language. Chapter 2 arrays and strings 97 This chapter introduces two pre-defined classes in Java: arrays and strings. They are also two types of data structures that must be processed by all programming languages. In traditional languages (such as C), arrays and strings are only a piece of continuous memory space, used to store the same type of data, and the language itself does not provide more support for it. Java designs it as an object and has more built-in methods, reducing the workload of programmers. In addition, Java will detect the subscript of the array. If there is any subscript out of bounds, it will be reported in a timely manner, avoiding a major problem plaguing C/C ++ programmers. Let's start with the array. Chapter 1 Process Control 6th what is process control? The process is the order of one thing, or the order. In program design, the process is to complete a function, and the process control is to control the order of completion of a function in the program design. A statement is a control component of a program. It has specific syntax rules and strict expressions to control the running of the program. Therefore, a statement is also a structured control structure. These control structures can be classified into three types: sequential structure, selection structure, and cyclic structure. Statements that implement these control structures can be divided into five types: expression statements, compound statements, branch statements, loop statements, and jump statements. This chapter describes these statements one by one. Chapter 5 Exception Handling and memory management 7th this problem is often encountered during actual project development. For example, a program does not produce error information during compilation, but when the program is running, some running Errors often occur, which is an exception for Java. An exception refers to an error or abnormal state that occurs when the program is running. If an exception occurs, a corresponding handling method is required. Exception Handling is an advantage of Java. In exception handling, its processing mechanism is well designed and easy to use, which not only improves the robustness of the program, it also greatly reduces the programming workload of programmers. Therefore, to successfully become a qualified Java programmer, mastering the exception handling mechanism is essential for writing large programs. Chapter 1 input/output stream 8th if an application does not have input or output, the user cannot provide the required information. Input and output are the interfaces provided by the entire application, allowing you to know what the application is intended for and what to do. For example, inputting some data on the keyboard, displaying the data on the display, and saving it into a file will involve information input/output processing. In Java, Information Input and Output (I/O) are an important part of programming languages. I/O refers to the data input and output by applications to these devices. In the program, the keyboard is used for file input, and the display is used for file output. Chapter 2 Object-Oriented Programming (OOP) is no stranger to the members of the IT field, because the first thing that comes into contact with OOP is from entering the IT field, every day, everyone is talking about oop. They need to have OOP ideas, but what is oop? What is oop? Whether I am a beginner in Java or a veteran who has been working for many years, I feel very confused about this problem and abstract it. My mind is just a vague concept, because the problem is abstracted, it is difficult to understand, so most recruitment companies use it as the evaluation standard. Therefore, how to understand OOP design ideas, inheritance and interfaces is a common test content in interviews. Chapter 1 multi-thread Java 10th so far, in traditional programming languages, most programmers are used to considering how to execute tasks sequentially from start to end, that is to say, a program has only one execution route, but many processes occur simultaneously in life. Java's "multithreading" can make up for this defect. It can run different program blocks together, make the program run more smoothly, and achieve the simultaneous processing of multiple tasks. Chapter 2 Package and access control 11th in Java, you can put classes and interfaces with similar functions and common properties into a file, which can be used to classify namespaces, you can also control access between classes. Compile and execute these files together, so that the program code is easier to maintain. At the same time, after the classes are separated, the corresponding access permissions are granted to the class usage. This chapter describes how to use packages and access control permissions. Chapter 1 class set framework 12th there are two important courses in computer science-data structures and algorithms-to show you how to accomplish common tasks. Because it is quite difficult for people to learn and understand the two, Java designers have designed a lot of methods to help programmers quickly surpass the gap, encapsulate common data structures and algorithms. These classes that process data structures and algorithms are stored in the collection library. This chapter introduces the usage of these classes. Chapter 2 database 13th This chapter describes how to use classes in the Java class library to write database applications. Databases play an important role in the program. Most practical applications use databases to store information. Databases and applications are independent of each other, databases are responsible for persistent data, and applications are responsible for business logic. To learn database programming, in addition to learning related classes such as JDBC in Java class libraries, you also need to learn the database query language-SQL, and learn this language specially designed for databases, you can write a database application in a Java program. After learning the language, you must learn the database software and perform visualized operations on the database. Large databases such as Oracle and MySQL. Chapter 2 J2EE (Java ee) and EJB 14th Technology Development 318j2ee are short for JAVA Platform Enterprise Edition (Java platform, Enterprise Edition). It contains a set of technical specifications and guidelines, including many components, it can simplify and standardize the development and deployment of application systems to improve portability, security, and reuse value. J2EE is based on Java SE, and a new class library is added for enterprise applications. Sun was initially named J2EE in its JAVA Platform Enterprise Edition and renamed Java EE 1.5 after J2EE 5.0. Java EE is the result of software technology development. Chapter 4 XML, UML, and mvc345 This chapter mainly describes the basic concepts and simple usage of XML and UML and the meaning of MVC. XML (Extensible Markup Language) is a new generation of data exchange standard released by the World Wide Web society (W3C). translating it into Chinese is "extensible markup language ". UML (Unified Modeling Language) is a modeling language and a main tool for requirement analysis and outline design. MVC (model, view, Controller) is the design mode of application development. M is the exponential data model; V is the user interface; C is the controller. Chapter 2 JSP/Servlet technology 16th in Java Development, JSP/servlet is a web layer technology, and JSP and Servlet are both sides of one, you can use a separate technology to address the demand for dynamic web page presentation, but the best way is to take the advantages of both. jsp is oriented by web page designers, servlet is guided by programmers. At present, most Java Development in China is Java Web development. clarifying their responsibilities allows two teams with different expertise to cooperate with each other, and reduce mutual restraint. Therefore, Servlet/JSP is also required in the Java programmer interview. Chapter 2 common questions on Java computers 17th the computer programming examination requires the interviewer to use a programming tool to write all the code and debug and run it according to the requirements of the questions. This is mainly to examine the examinee's proficiency in code writing and programming. It is worth noting that such interview questions require proper running, and usually require the interviewer to use the original JDK compilation method, that is, to use the doscommand prompt, rather than providing a rapid development environment such as eclipse or JBuilder. This chapter classifies frequently-encountered computer programming questions, hoping to help and inspire readers. Chapter 1 thinking and Intelligence Testing 18th this type of interview questions puts forward higher requirements for the interviewer. Questions about thinking expansion can be divided into two categories. One is thinking extended programming. First, the interviewer needs to establish a programming model and then use code programming to give answers. The other is intelligence testing, measure the test taker's knowledge about how to think and respond to the problem. No programming is required to solve the problem.