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What will be displayed as a result of executing the following code?
What will be displayed as a result of executing the following code?
This is an interactive program that lets you enter Java programming statements and immediately see each statement's results. What is it called?
This is an interactive program that lets you enter Java programming statements and immediately see each statement's results. What is it called?
If you use this keyword to declare a local variable, you do not have to specify the variable's data type.
If you use this keyword to declare a local variable, you do not have to specify the variable's data type.
How would you rewrite the following statement using the word var to declare the variable? int value = 99;
How would you rewrite the following statement using the word var to declare the variable? int value = 99;
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Programming style includes techniques for consistently putting spaces and indentation in a program to help create visual cues.
Programming style includes techniques for consistently putting spaces and indentation in a program to help create visual cues.
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Both character and string literals can be assigned to a char variable.
Both character and string literals can be assigned to a char variable.
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A variable's scope is the part of the program that has access to that variable.
A variable's scope is the part of the program that has access to that variable.
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Named constants are initialized with a value and that value cannot change during the execution of the program.
Named constants are initialized with a value and that value cannot change during the execution of the program.
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When you call one of the Scanner class's methods to read a primitive value, such as nextInt or nextDouble, and then call the nextLine method to read a string, an annoying and hard-to-find problem can occur.
When you call one of the Scanner class's methods to read a primitive value, such as nextInt or nextDouble, and then call the nextLine method to read a string, an annoying and hard-to-find problem can occur.
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Class names and keywords are examples of variables.
Class names and keywords are examples of variables.
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The Java API provides a class named Math that contains numerous methods which are useful for performing complex mathematical operations.
The Java API provides a class named Math that contains numerous methods which are useful for performing complex mathematical operations.
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The System.out.printf method allows you to format output in a variety of ways.
The System.out.printf method allows you to format output in a variety of ways.
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A Java program will not compile unless it contains the correct line numbers.
A Java program will not compile unless it contains the correct line numbers.
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Java is not case sensitive.
Java is not case sensitive.
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If the compiler encounters a statement that uses a variable before the variable is declared, an error will result.
If the compiler encounters a statement that uses a variable before the variable is declared, an error will result.
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If you use the var keyword to declare a variable, you cannot initialize the variable with a value.
If you use the var keyword to declare a variable, you cannot initialize the variable with a value.
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Which of the following is a value that is written into the code of a program?
Which of the following is a value that is written into the code of a program?
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A Java program must have at least one of the following:
A Java program must have at least one of the following:
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Which of the following would contain the translated Java byte code for a program named Demo?
Which of the following would contain the translated Java byte code for a program named Demo?
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Which of the following is a named storage location in the computer's memory?
Which of the following is a named storage location in the computer's memory?
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Which of the following is not a valid Java comment?
Which of the following is not a valid Java comment?
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To compile a program named First you would use which of the following commands?
To compile a program named First you would use which of the following commands?
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A Java source file must be saved with the extension:
A Java source file must be saved with the extension:
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Which of the following is not a rule that must be followed when naming identifiers?
Which of the following is not a rule that must be followed when naming identifiers?
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Character literals are enclosed in ________ and string literals are enclosed in ________.
Character literals are enclosed in ________ and string literals are enclosed in ________.
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Variables are classified according to their:
Variables are classified according to their:
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What is the result of the following expression? $5 + 2$
What is the result of the following expression? $5 + 2$
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What is the result of the following expression? $-5 + 10$
What is the result of the following expression? $-5 + 10$
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In the following Java statement, what value is stored in the variable name?
In the following Java statement, what value is stored in the variable name?
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What is the value of z after the following statements have been executed? $z = 5 + 3$
What is the value of z after the following statements have been executed? $z = 5 + 3$
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What output will be displayed as a result of executing the following code? System.out.println(x + z);
What output will be displayed as a result of executing the following code? System.out.println(x + z);
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Which of the following statements will correctly convert the data type, if x is a float and y is a double?
Which of the following statements will correctly convert the data type, if x is a float and y is a double?
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Which of the following statements is invalid?
Which of the following statements is invalid?
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To print "Hello, world" on the monitor, which of the following Java statements should be used?
To print "Hello, world" on the monitor, which of the following Java statements should be used?
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The boolean data type may contain which of the following range of values?
The boolean data type may contain which of the following range of values?
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Variables of the boolean data type are useful for:
Variables of the boolean data type are useful for:
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What would be displayed as a result of executing the following code? System.out.println("There are 5785 hens in the hen house.");
What would be displayed as a result of executing the following code? System.out.println("There are 5785 hens in the hen house.");
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What would be displayed as a result of executing the following code? System.out.println(x);
What would be displayed as a result of executing the following code? System.out.println(x);
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What would be displayed as a result of executing the following code? System.out.println("This is a simple message.");
What would be displayed as a result of executing the following code? System.out.println("This is a simple message.");
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What is the value of z after the following code is executed? z = 5
What is the value of z after the following code is executed? z = 5
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Which of the following statements correctly creates a Scanner object for keyboard input?
Which of the following statements correctly creates a Scanner object for keyboard input?
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Which Scanner class method reads a String?
Which Scanner class method reads a String?
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The primitive data types only allow a(n) ________ to hold a single value.
The primitive data types only allow a(n) ________ to hold a single value.
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In Java, ________ must be declared before they can be used.
In Java, ________ must be declared before they can be used.
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A value that is written into the code of a program is a(n) ________.
A value that is written into the code of a program is a(n) ________.
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When the + operator is used with strings, it is known as the:
When the + operator is used with strings, it is known as the:
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Which of the following is not a rule that must be followed when naming identifiers?
Which of the following is not a rule that must be followed when naming identifiers?
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Which of the following cannot be used as identifiers in Java?
Which of the following cannot be used as identifiers in Java?
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Which of the following is not a primitive data type?
Which of the following is not a primitive data type?
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Which of the following is valid?
Which of the following is valid?
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If x has been declared an int, which of the following statements is invalid?
If x has been declared an int, which of the following statements is invalid?
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To display the output on the next line, you can use the println method or use the ________ escape sequence in the print method.
To display the output on the next line, you can use the println method or use the ________ escape sequence in the print method.
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Every Java application program must have:
Every Java application program must have:
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What will be displayed as a result of executing the following code?
What will be displayed as a result of executing the following code?
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Study Notes
Java Fundamentals
- Programming style enhances readability through space and indentation.
- Only string literals, not character literals, can be assigned to a String variable.
- Variable scope defines the area of the program that can access the variable.
- Named constants remain unchanged during program execution after initialization.
- Calling nextInt or nextDouble from the Scanner class before nextLine can produce unexpected results.
- Class names and keywords do not qualify as variables.
- The Math class in the Java API provides methods for complex mathematical operations.
- The System.out.printf method formats output in various styles.
- Java compilation does not require line numbers.
- Java is case-sensitive; variable names must be treated distinctly based on letter casing.
- Using an undeclared variable results in a compile-time error.
- The var keyword allows variable declarations without specifying the data type, but initialization is still permitted.
Multiple Choice Highlights
- Literals are values coded directly into the program.
- Each Java program requires at least one class definition.
- Java byte code for a program is stored in a file with a .class extension.
- Variables serve as named storage locations in memory.
- Invalid Java comments include improper opening and closing syntax.
- To compile a Java program, use the javac command with the .java extension.
- Identifiers in Java cannot contain spaces; they must start with a letter, underscore, or dollar sign.
- Character literals are enclosed in single quotes while string literals require double quotes.
- Variables are classified based on data types which determine the kind of values they can hold.
- Boolean values in Java can only be true or false.
Key Concepts on Variables and Data Types
- Literal values can only be stored in variables of compatible data types.
- All variables must be declared before use in Java.
- A Scanner object facilitates keyboard input by using
new Scanner(System.in). - To change a float to a double, casting is required with
(float)y. - Primitive data types like int, char, boolean, etc., do not include complex types such as String or Object.
- Escape sequences like
\ncan be used for generating new lines in output. - Every Java application requires a main method as an entry point.
Error Handling and Code Execution Results
- Executing code can sometimes reveal errors related to improper syntax or invalid statements.
- Display formats for output can visually represent variables and strings combined.
- The result of mathematical expressions in code can vary dramatically based on operands used.
- Functions like nextLine read the entire line of input, while others, like nextInt, only capture the numeric portion.
- The System.out.println command can be used to output strings to the console effectively.
Additional Insights
- Interactive programming environments are available for testing Java snippets, like JShell.
- Study the differences between primitive and reference data types as well as best practices for naming conventions in Java.
- Familiarity with logical expressions and conditions will enhance understanding of boolean types and their applications in control structures.
Studying That Suits You
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Description
Test your knowledge of Java fundamentals with this true/false quiz based on Chapter 2 of 'Starting Out with Java: From Control Structures through Objects'. Each question focuses on key concepts such as programming style, variables, and constants. Challenge yourself and gauge your understanding of these essential Java principles!
