Use primitives and wrapper classes. Evaluate arithmetic and boolean expressions, using the Math API and by applying precedence rules, type conversions, and casting.
Manipulate text, including text blocks, using String and StringBuilder classes.
1. The correct answer is C.
Explanation:
double can be directly assigned to a float without casting.
double cannot be directly assigned to a float without casting because double has a larger range and precision than a float.boolean can be cast to an int.
boolean values cannot be cast to int in Java. They are not compatible types.String can be assigned to an Object reference variable.
String is an instance of the Object class, and hence it can be assigned to an Object reference variable.char is a reference data type.
char is a primitive data type, not a reference data type.int can store a long value without any explicit casting.
int cannot store a long value without explicit casting because long has a larger range than int.2. The correct answer is A.
Explanation:
Let’s break down the expression a + b * c / a - b step-by-step according to the order of operations:
b * c = 10 * 15 = 150150 / a = 150 / 5 = 30a + 30 = 5 + 30 = 3535 - b = 35 - 10 = 25So, the value of result is 25, and the program prints 25.
25
35
20
15
3. The correct answer is D.
Explanation:
StringBuilder objects are immutable.
StringBuilder objects are mutable, meaning they can be changed after they are created.String objects can be modified after they are created.
String objects are immutable, meaning once a String object is created, it cannot be modified. Any modification results in a new String object.StringBuilder is synchronized and thread-safe.
StringBuilder is not synchronized and is not thread-safe. If synchronization is required, StringBuffer should be used instead.StringBuilder provides methods for mutable sequence of characters.
StringBuilder provides methods for a mutable sequence of characters, allowing for modification of the object without creating new instances.String and StringBuilder have the same performance characteristics for string manipulation.
String and StringBuilder do not have the same performance characteristics for string manipulation. StringBuilder is generally more efficient for such operations because it is mutable and does not create new instances with each modification.4. The correct answers are A and B.
Explanation:
String can be used, not just within methods. They can be part of class fields, method parameters, etc.5. The correct answer is D.
Explanation:
Math.round() method returns a double.
Math.round() method returns a long when given a double argument and an int when given a float argument.Math.random() method returns a random integer.
Math.random() method returns a double value between 0.0 (inclusive) and 1.0 (exclusive).Math.max() method can only be used with integers.
Math.max() method can be used with various numeric types, including int, long, float, and double.Math.pow() method returns the result of raising the first argument to the power of the second argument.
Math.pow() method returns the result of raising the first argument to the power of the second argument. Both arguments are of type double.Math.abs() method can only be used with positive numbers.
Math.abs() method can be used with negative numbers to return their absolute value, and it works with various numeric types including int, long, float, and double.Do you like what you read? Would you consider?
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