Oracle Certified Professional: Java SE 11 Developer (1Z0-819) Practice Test
Gana confianza para Oracle Certified Professional: Java SE 11 Developer (1Z0-819). Practica los conceptos, comprende las respuestas y refuerza tus conocimientos pregunta a pregunta.
Probar una preguntaDescripción y detalles del examen
La certificación Oracle Certified Professional: Java SE 11 Developer (1Z0-819) es el estándar de la industria para validar la competencia profesional en programación Java, y una de las certificaciones de desarrollo de software más reconocidas a nivel mundial. El examen cubre Java fundamentals, object-oriented programming principles, exception handling, Java APIs including collections and streams, functional programming with lambdas, the Java Platform Module System (JPMS) introducido en Java 9, concurrent programming, I/O operations, y database access with JDBC. Java SE 11 es una versión de long-term support (LTS), lo que hace que esta certificación sea particularmente valiosa para roles de desarrollo empresarial donde la estabilidad es crítica, y el OCP Java SE 11 Developer combina los objetivos de Java SE 11 Programmer I (1Z0-815) y Programmer II (1Z0-816) en un solo examen integral.
Preguntas de Muestra
Elige una respuesta y consulta la explicación para ver cómo funciona la práctica.
A developer is building a modular Java application and needs to use the JDBC API to connect to a relational database. Which module must be required in the module descriptor to access the JDBC interfaces?
El API de JDBC está definido en el módulo java.sql, como se indica en la lista de módulos de Java SE. El módulo java.base contiene las APIs fundamentales pero no incluye JDBC. No existe un módulo jdk.jdbc; JDBC forma parte de Java SE, no de JDK‑específico. El módulo java.naming proporciona JNDI, que es independiente de JDBC. Por lo tanto, un descriptor de módulo debe incluir:
requires java.sql;para acceder a las interfaces de JDBC.
A developer is building a Java SE application that must authenticate to a remote service using Kerberos tickets. Which module should be used to access the necessary security APIs?
Kerberos authentication in Java is provided through the Generic Security Services API (GSS-API), which is defined in the java.security.jgss module. The SASL module (java.security.sasl) supports other authentication mechanisms but not Kerberos directly. The RMI connector module (java.management.rmi) is for JMX remote management, and the JNDI module (java.naming) is for naming and directory services, neither of which provides Kerberos authentication APIs.
A developer is building a Java SE application that must run on any conforming Java SE 11 implementation, including those that are not the reference JDK. Which module is guaranteed to be available for the application to use?
El Java SE Platform define un conjunto de APIs centrales que están garantizadas para estar presentes en cualquier implementación conforme. Estas APIs están organizadas en módulos cuyos nombres comienzan con 'java'. El módulo java.base contiene APIs fundamentales como java.lang y java.util, y siempre está disponible. Los módulos cuyos nombres comienzan con 'jdk' son específicos del JDK y no están garantizados para estar presentes en todas las implementaciones de Java SE; pueden estar ausentes en implementaciones alternativas o entornos de ejecución. Por lo tanto, solo java.base está asegurado de estar disponible.
A developer is designing a new class that represents a network connection and needs to provide a method that reports whether the connection is currently active. Following the standard Java naming conventions, what should the method be named?
Las convenciones de nomenclatura de Java especifican que los métodos que prueban una condición booleana sobre un objeto deben nombrarse con el prefijo 'is' seguido del nombre de la condición. Esto hace que el propósito del método sea claro y consistente con la API de la Plataforma Java SE. Las otras opciones no siguen esta convención: 'active()' carece del prefijo 'is', 'checkActive()' no es un nombre estándar para un verificador booleano, y 'getActive()' se utiliza típicamente para acccesores de propiedades en lugar de pruebas booleanas.
A developer is maintaining a widely distributed Java library. They need to modify an existing class without breaking binary compatibility for clients who have already compiled against the previous version. Which of the following changes is guaranteed to preserve binary compatibility?
Binary compatibility ensures that pre-existing compiled code continues to work without recompilation when a library is updated. Adding new fields, methods, or constructors to an existing class is explicitly permitted and does not break existing binaries because existing code does not reference the new members. Deleting a public field breaks compatibility because existing code may access that field directly, and the field will no longer exist. Changing the return type of a public method breaks compatibility because the method descriptor changes, causing a NoSuchMethodError when existing code attempts to invoke it. Reordering parameters similarly changes the method descriptor, breaking invocation from pre-compiled clients.
Oportunidades profesionales y salario
Los rangos son cifras del mercado de EE. UU. salvo que se muestre un rango local.
Qué temas cubre este examen
01Annotations
This specific domain involves creating custom annotations, applying annotations within Java code structures, and processing annotations dynamically during application execution and compilation phases according to official language specifications.
Temas
- Create, apply, and process annotations
Objetivos de aprendizaje
- Create, apply, and process annotations
02Concurrency
This domain focuses on worker threads using Runnable and Callable, managing concurrency using ExecutorService and the java.util.concurrent API, and developing thread-safe code utilizing different locking mechanisms for high-performance applications.
Temas
- Create worker threads using Runnable and Callable, and manage concurrency using an ExecutorService and java.util.concurrent API
- Develop thread-safe code, using different locking mechanisms and java.util.concurrent API
Objetivos de aprendizaje
- Create worker threads using Runnable and Callable, and manage concurrency using an ExecutorService and java.util.concurrent API
- Develop thread-safe code, using different locking mechanisms and java.util.concurrent API
03Controlling Program Flow
This domain focuses on controlling program execution using loops, if/else conditional structures, and switch statements to direct logical flow within Java SE applications according to official Oracle requirements.
Temas
- Create and use loops, if/else, and switch statements
Objetivos de aprendizaje
- Create and use loops, if/else, and switch statements
04Database Applications with JDBC
This specific domain focuses heavily on connecting to databases, performing SQL operations, and processing query results using the JDBC API to build database-driven Java SE enterprise applications successfully without issues.
Temas
- Connect to and perform database SQL operations, process query results using JDBC API
Objetivos de aprendizaje
- Connect to and perform database SQL operations, process query results using JDBC API
05Exception Handling
This domain deals with error management via try/catch/finally blocks, try-with-resource statements, multi-catch clauses, and custom exceptions to ensure reliable exception handling across enterprise Java SE software deployment projects.
Temas
- Handle exceptions using try/catch/finally clauses, try-with-resource, and multi-catch statements
- Create and use custom exceptions
Objetivos de aprendizaje
- Handle exceptions using try/catch/finally clauses, try-with-resource, and multi-catch statements
- Create and use custom exceptions
06Java I/O API
This domain addresses reading and writing console and file data using I/O Streams, implementing serialization and deserialization techniques on Java objects, and handling file system objects using the java.nio.file API.
Temas
- Read and write console and file data using I/O Streams
- Implement serialization and deserialization techniques on Java objects
- Handle file system objects using java.nio.file API
Objetivos de aprendizaje
- Read and write console and file data using I/O Streams
- Implement serialization and deserialization techniques on Java objects
- Handle file system objects using java.nio.file API
07Java Object-Oriented Approach
This domain explores object lifecycles, nested classes, instance members, static members, overloaded methods, instance initializers, static initializer statements, and object initialization constructors required for developing proper object-oriented Java SE applications.
Temas
- Declare and instantiate Java objects including nested class objects, and explain objects' lifecycles (including creation, dereferencing by reassignment, and garbage collection)
- Define and use fields and methods, including instance, static and overloaded methods
- Initialize objects and their members using instance and static initialiser statements and constructors
- Understand variable scopes, apply encapsulation and make objects immutable
- Create and use subclasses and superclasses, including abstract classes
- Utilize polymorphism and casting to call methods, differentiate object type versus reference type
- Create and use interfaces, identify functional interfaces, and utilize private, static, and default methods
- Create and use enumerations
Objetivos de aprendizaje
- Declare and instantiate Java objects including nested class objects, and explain objects' lifecycles (including creation, dereferencing by reassignment, and garbage collection)
- Define and use fields and methods, including instance, static and overloaded methods
- Initialize objects and their members using instance and static initialiser statements and constructors
- Understand variable scopes, apply encapsulation and make objects immutable
- Create and use subclasses and superclasses, including abstract classes
- Utilize polymorphism and casting to call methods, differentiate object type versus reference type
- Create and use interfaces, identify functional interfaces, and utilize private, static, and default methods
- Create and use enumerations
08Java Platform Module System
This domain covers the Java Platform Module System, automatic modules, declaring modules, using modules, exposing modules, service usage, and modular application deployment and execution for modern Java platform architectures.
Temas
- Deploy and execute modular applications, including automatic modules
- Declare, use, and expose modules, including the use of services
Objetivos de aprendizaje
- Deploy and execute modular applications, including automatic modules
- Declare, use, and expose modules, including the use of services
09Localization
This specific domain explores localization through Locale objects, resource bundles, and Java APIs designed carefully to parse and format messages, dates, and numbers for international software deployment across global markets.
Temas
- Implement Localization using Locale, resource bundles, and Java APIs to parse and format messages, dates, and numbers
Objetivos de aprendizaje
- Implement Localization using Locale, resource bundles, and Java APIs to parse and format messages, dates, and numbers
10Secure Coding in Java SE Application
This domain covers mitigation of security threats like denial of service, code injection, input validation, data integrity assurance, secure resource access for filesystems, policy management, and execution of privileged code.
Temas
- Develop code that mitigates security threats such as denial of service, code injection, input validation and ensure data integrity
- Secure resource access including filesystems, manage policies and execute privileged code
Objetivos de aprendizaje
- Develop code that mitigates security threats such as denial of service, code injection, input validation and ensure data integrity
- Secure resource access including filesystems, manage policies and execute privileged code
11Working with Arrays and Collections
This domain addresses generics, wildcards, Java arrays, List collections, Set collections, Map collections, Deque collections, convenience methods, and sorting data using Comparator and Comparable interfaces for efficient data structures.
Temas
- Use generics, including wildcards
- Use a Java array and List, Set, Map and Deque collections, including convenience methods
- Sort collections and arrays using Comparator and Comparable interfaces
Objetivos de aprendizaje
- Use generics, including wildcards
- Use a Java array and List, Set, Map and Deque collections, including convenience methods
- Sort collections and arrays using Comparator and Comparable interfaces
12Working with Java data types
This domain covers primitives, wrapper classes, operators, parentheses, type promotion, type casting, text handling with String and StringBuilder classes, and local variable type inference including usage as lambda parameters within Java SE applications.
Temas
- Use primitives and wrapper classes, including, operators, parentheses, type promotion and casting
- Handle text using String and StringBuilder classes
- Use local variable type inference, including as lambda parameters
Objetivos de aprendizaje
- Use primitives and wrapper classes, including, operators, parentheses, type promotion and casting
- Handle text using String and StringBuilder classes
- Use local variable type inference, including as lambda parameters
13Working with Streams and Lambda expressions
This domain involves functional interfaces, lambda expressions from the java.util.function package, data processing with Java Streams, filtering, transformation, decomposition, reduction, grouping, and partitioning on sequential and parallel streams.
Temas
- Implement functional interfaces using lambda expressions, including interfaces from the java.util.function package
- Use Java Streams to filter, transform and process data
- Perform decomposition and reduction, including grouping and partitioning on sequential and parallel streams
Objetivos de aprendizaje
- Implement functional interfaces using lambda expressions, including interfaces from the java.util.function package
- Use Java Streams to filter, transform and process data
- Perform decomposition and reduction, including grouping and partitioning on sequential and parallel streams