基础知识（1）- Java SE 8 Programmer I (1z0-808)

Java Basics 

• Define the scope of variables
• Define the structure of a Java class
• Create executable Java applications with a main method; run a Java program from the command line; including console output.
• Import other Java packages to make them accessible in your code
• Compare and contrast the features and components of Java such as: platform independence, object orientation, encapsulation, etc.

Working With Java Data Types 

• Declare and initialize variables (including casting of primitive data types)
• Differentiate between object reference variables and primitive variables
• Know how to read or write to object fields
• Explain an Object‘s Lifecycle (creation, "dereference by reassignment" and garbage collection)
• Develop code that uses wrapper classes such as Boolean, Double, and Integer.

Using Operators and Decision Constructs 

• Use Java operators; including parentheses to override operator precedence
• Test equality between Strings and other objects using == and equals ()
• Create if and if/else and ternary constructs
• Use a switch statement

Creating and Using Arrays 

• Declare, instantiate, initialize and use a one-dimensional array
• Declare, instantiate, initialize and use multi-dimensional array

Using Loop Constructs 

• Create and use while loops
• Create and use for loops including the enhanced for loop
• Create and use do/while loops
• Compare loop constructs
• Use break and continue

Working with Methods and Encapsulation 

• Create methods with arguments and return values; including overloaded methods
• Apply the static keyword  to methods and fields
• Create and overload constructors; including impact on default constructors
• Apply access modifiers
• Apply encapsulation principles to a class
• Determine the effect upon object references and primitive values when they are passed  into methods that change the values

Working with Inheritance 

• Describe inheritance and its benefits
• Develop code that demonstrates the use of polymorphism; including overriding and object type versus reference type
• Determine when casting is necessary
• Use super and this to access objects and constructors
• Use abstract classes and interfaces

Handling Exceptions 

• Differentiate among checked exceptions, unchecked exceptions, and Errors
• Create a try-catch block and determine how exceptions alter normal program flow
• Describe the advantages of Exception handling
• Create and invoke a method that throws an exception
• "Recognize common exception classes (such as NullPointerException, ArithmeticExcpetion, ArrayIndexOutOfBoundsException, ClassCastException)"

Working with Selected classes from the Java API 

• Manipulate data using the StringBuilder class and its methods
• Creating and manipulating Strings
• Create and manipulate calendar data using classes from java.time.LocalDateTime,  java.time.LocalDate, java.time.LocalTime, java.time.format.DateTimeFormatter, java.time.Period
• Declare and use an ArrayList of a given type
• Write a simple Lambda expression that consumes a Lambda Predicate expression