Java Review - Part 2

methods
Functions that can be performed on an object

static
public class Simple {
public ______ void main(String args[])
}

void
public class Simple {
public static ____ main(String args[])
}

main
public class Simple {
public static void ____(String args[])
}

args[]
public class Simple {
public static void main(String _____)
}

String
public class Simple {
public static void main(____ args[])
}

-cp
// to compile
javac ___ <classesPaths> -d <compilerOutputPath> <pathToSource>.java

classesPaths
// to compile
javac -cp <_______> -d <compilerOutputPath> <pathToSource>.java

-d
// to compile
java -cp <classesPaths> __ <compilerOutputPath> <pathToSource>.java

compilerOutputPath
// to compile
java ___ <classesPaths> -d <_________> <pathToSource>.java

pathToSource
// to compile
java -cp <classesPaths> -d <compilerOutputPath> <_________>.java

.java
// to compile
java ___ <classesPaths> -d <compilerOutputPath> <pathToSource>______

if
// if statement
____ (a == b) {
System.out.println('True');
} else {
System.out.println('False');
}

else
// if statement
if (a == b) {
System.out.println('True');
} ____ {
System.out.println('False');
}

switch
// switch statement
_____ (color) {
case 'Blue':
shirt = 'Blue' + shirt;
break;
case 'Red':
shirt = 'Red' + shirt;
break;
default:
shirt = 'White' + shirt;
}

case
// switch statement
switch (color) {
_____ 'Blue':
shirt = 'Blue' + shirt;
break;
_____ 'Red':
shirt = 'Red' + shirt;
break;
default:
shirt = 'White' + shirt;
}

default
// switch statement
_____ (color) {
case 'Blue':
shirt = 'Blue' + shirt;
break;
case 'Red':
shirt = 'Red' + shirt;
break;
_____:
shirt = 'White' + shirt;
System.out.println('' + shirt);
}

while
// while loop
_____ (x < 20) {
System.out.print('x: ' + x);
x++;
System.out.print('\n');
}

()
// while loop
while _x < 20_ {
System.out.print('x: ' + x);
x++;
System.out.print('\n');
}

for
// for loop
____ (int i = 0; i < 9; i++) {
System.out.println('' + i);
}

;
// for loop
for (int i = 0_ i < 9_ i++) {
System.out.println('' + i);
}

++
// for loop
for (int i = 0; i < 9; i__) {
System.out.println('' + i);
}

name
//iterate over array of int
int[] numbers = {100,200,300};
for (String ____:names){
System.out.println('Name' + name);
}

names
//iterate over array of int
int[] numbers = {100,200,300};
for (String name:____){
System.out.println('Name' + name);
}

StringBuilder
//creating StringBuilder
_______ sb = new StringBuilder('hello');

new
//creating StringBuilder
StringBuilder sb = ___ StringBuilder('hello');

append
//adding to a StringBuilder instance
StringBuilder sb = new StringBuilder('hello');
sb.______(', how are you?');

insert
//how to insert
sb._____(::number::, ' Fine');

length
//how to get a length of StringBuilder
sb.______()

ClassName
//build a constructor in a class
public ________ () {
}

mutators
Methods that set the value of each field are called ______

this
//build a class accessor
public void setId (int id) {
____.Id = id;
}

new
//create an instance
ClassName cn = ___ ClassName();

namespace
A package is implemented as a folder and, like a folder, provides a _______ to a class

//com.example.domain
+com
|_+example
|_+domain
|_+Employee.java
|_+Manager.java

reference
For Java objects, the value of the right side of an assignment is a ________ to memory that stores a Java object

130000.0
//what does this return?
public class ObjectPassTest {
public static void main(String[] args) {
ObjectPassTest test = new ObjectPassTest();
Employee x = new Employee();
x.setSalary(120_000.00);
test.foo(x);
System.out.println('' + x.getSalary());
}
public void foo(Employee e){
e.setSalary(130_000.00);
e = new Employee();
e.setSalary(140_000.00);
}
}

hashCode
It is necessary to override the ______ method whenever this the equals method is overridden

...
//make this varargs friendly
public class Statistics {
public float average(int___ nums) {
int sum = 0;
for (int x: nums) {
sum += x;
}
return ((float) sum / nums.length
}
}

Manager
//make code compile
public static void main(String[] args){
Employee e = new Manager();
if (e instanceof Manager){
Manager m = ( _____ ) e;
m.setDeptName('HR');
System.out.println(m.getDetails());
}
}

initializer
The static _______ block is a code block prefixed by the static keyword

//example
static boolean[] switches = new boolean[5];
_____ {
System.out.println('');
for (int i=0; i<5; i++) {
switches[i] = true;
}
}

import
A static _____ statement makes the static members of a class available under their simple name

//example
_____ static java.lang.Math.random;
import static java.lang.Math. - ;

public class StaticImport {
public static void main(String[] args) {
double d = random();
}
}

singleton
The ______ design pattern details a class implementation that can be instantiated only once

final
//make a Singleton
public class SingletonClass {
private static ____ SingletonClass instance = new SingletonClass();
private SingletonClass() {}
public static SingletonClass getInstance() {
return instance;
}
}

arguments
An abstract method can take ______ and return values

child
When inheriting from an abstract class, you must do either of the following:
(1) Declare the _______ class as abstract
(2) Override all abstract methods inherited from the parent class.

methods
When inheriting from an abstract class, you must do either of the following:
(1) Declare the child class as abstract
(2) Override all abstract ______ inherited from the parent class.

compile
Enumerations provide a ______-time range check

enum
//make an enumeration
public _____ PowerState {
OFF,
ON,
SUSPEND;
}

extends
If you use both extends and implements, ________ must come first

new
//Make an Anonymous inner class
Z04Analyzer.searchArr(strList01,
___ StringAnalyzer() {
@Override
public boolean analyze(String target, String searchStr) {
return target.contains(searchStr);
}
}
});

generics
_________ provide flexible type safety to your code, reduce the need for casting with collections and move many common errors from run time to compile time

cache
//example of a simple ______ class
public class CacheString {
private String message;
public void add(String message){ this.message = message;
}
public String get(){
return this.message;
} }

generic
//example of a _______ class
public class CacheAny<T> {
private T t;
public void add(T t) {
this.t = t;
}
public T get() {
return this.t;
}
}

types
With generics, S and U are used if there are second or third ______

<String>
//Write generic of the following
CacheString myMessage = new CacheString();
CacheAny_____ myGenericMessage = new CacheAny_____();

()
//Write generic of the following
CacheString myMessage = new CacheString();
CacheAny<String> myGenericMessage = new CacheAny<String>__;

<>
//Use generics to add compile time check
List partList = new ArrayList(3);

List<Integer> partList = new ArrayList__(3);

Unbox
//_____ Integer collection
for (Integer partNumberObj:partList) {
int partNumber = partNumberObj;
System.out.println('Part number: ' + partNumber);
}

null
A HashMap implementation justlike Hashtable except that it accepts ____ keys and values

()
//implement a TreeMap
public class MapExample {
public static void main(String[] args) {
Map<String, String> partList = new TreeMap<>__;
//....
}
}

<>
//implement a TreeMap
public class MapExample {
public static void main(String[] args) {
Map<String, String> partList = new TreeMap__();
//....
}
}

TreeMap
//implement a TreeMap
public class MapExample {
public static void main(String[] args) {
Map<String, String> partList = new ______<>();
//....
}
}

deque
A ______ is a 'doubled-ended queue'

ArrayDeque
//example of a _______
public class Teststack {
public static void main(String[] args) {
Deque<String> stack = new ________<>();
stack.push('one');
}
}

sorting
The Comparator interface enables you to create and use numerous ______ options

Builder
//example of the ______ pattern
people.add(
new Person.______()
.givenName('Betty')
.surName('Jones')
.age(85)
.gender(Gender.FEMALE)
);

variable
//use of lambdas as a ______
Predicate<Person> allPilots = p -> p.getAge() >= 23 && p.getAge() <= 65;

p1.stream().filter(allPilots).forEach(p -> rob.roboCall(p));

::
//make reference to a static method
ContainingClass__staticMethodName

supplier
In the context of a stream this provides an instance of a T (such as a factory)

predicate
//example of _____
package java.util.function;
public interface ______<T> {
public boolean test(T t);
}

consumer
//example of a _____
______<SalesTxn> buyer = t -> System.out.println('Id: ' + t.getTxnId() + ' Buyer: ' + t.getBuyer().getName());
System.out.println('== Buyers - Lambda');
tList.stream().forEach(buyer);
System.out.println('== First Buyer - Method');
buyer.accept(first);

Function
//example of a ______
package java.util._____;
public interface ______<T, R> {
public R apply(T t);
}

Supplier
//example of a _____
package java.util.function;

public interface _______<T> {
public T get();
}

double
//complete primitive type return
package java.util.function;
public interface ToDoubleFunction<T> {
public ____ applyAsDouble(T t);
}

R
//process a primitive type
package java.util.function;
public interface DoubleFunction<R> {
public __ apply(double value);
}

boolean
//complete a BiPredicate
package java.util.function;
public interface BiPredicate<T, U> {
public ______ test(T t, U u);
}

T
//take class as input and return
//object of the same class
package java.util.function;
public interface UnaryOperator<T> extends Function<T, T> {
@Override
public __ apply(T t);
}

super
//accept this & any parent types
? _____ T

extends
//accept this & any child types
? ______ T

result
A terminal operation in a store pipeline produces a _____ or side effect

intermediate
//stream methods
//below: examples of _____
//operations
filter() --- map() --- peek()

terminal
//stream methods
//below: examples of ____
//operations
forEach() --- count() --- sum() --- average() --- min() --- max() --- collect()

short-circuit
//stream methods
//each below is a Terminal ___
findFirst() --- findAny() --- anyMatch() --- allMatch() --- noneMatch()

map
A ____ takes one Function as an argument. A Function takes one generic and returns something else
//code
___(Function<? super T, ? extends R> mapper)

peek
The ____ method performs the operation specified by the lambda expression and returns the elements to the stream.
//code
_(Consumer<? super T> action)

max
//in stream return biggest
//element of this stream
//according to Comparator
__(Comparator<? super T> comparator)

min
//in stream return smallest
//element of this stream
//according to Comparator
__(Comparator<? super T> comparator)

Comparator
//return sort according 2 comp
sorted(______<? super T> comparator)

comparing
The _______ method allows you to specify any field to sort on based on a method reference or lambda
//_(Function<?superT,?extendsU> keyExtractor)

collect
The ______ method allows you to save the result of a stream to a new data structure
//example
stream().collect(Collectors.toList());

averagingDouble
The ______ method of the Collectors class produces the arithmetic mean of a double-valued function applied to the input elements
//code
averagingDouble(ToDoubleFunction<? super T> mapper)

groupingBy
The ______ method of the Collectors class operates on input elements of type T, grouping elements according to a classification function, and returning the results in a map
//code
_(Function<?superT,?extendsK>classifier)

joining
The ___ method of the Collectors class concatenates the input elements into a String, in encounter order

partitioningBy
The _____ method of the Collectors class partitions the input elements according to a Predicate
//code
_(Predicates<?superT>predicate)

of
The Stream.__ method allows you to easily create a stream
//example
Stream.of('Monday','Tuesday').filter(s -> s.startsWith('T')).forEach(s -> System.out.println('Matching Days: ' + s));

catch
//complete
try {
InputStream in = new FileInputStream('missing file.txt');
} __ (Exception e) {
System.out.println('Something went wrong');
}

try
//complete
__ {
InputStream in = new FileInputStream('missing file.txt');
} catch (Exception e) {
System.out.println('Something went wrong');
}

finally
//complete
try {
in = new FileInputStream('missing file.txt');
} catch (IOException e) {
System.out.println(e.getMessage());
} __ {
try {
if(in != null) in.close();
} catch(IOException e) {
System.out.println('Failed to close file');
}
}

IOException
//complete
try {
in = new FileInputStream('missing file.txt');
} catch (______ e) {
System.out.println(e.getMessage());
} finally {
try {
if(in != null) in.close();
} catch(IOException e) {
System.out.println('Failed to close file');
}
}

try-with-resources
//example of _______
try(InputStream in = new FileInputStream('missing file.txt')) {
System.out.println('File open');
int data = in.read();
} catch ...

|
//perform multi-catch
try () {
} catch (ClassNotFoundException _ IOException e) {
System.out.println();
}

throws
//complete
public static int readByte() _____ IOException {...}

:
//descriptive assertion
assert booleanExpression _ expression;

assert
//complete assertion
_____ booleanExpression;

internal
//ex. of __ invariant use
int x = num;
if (x > 0) {
System.out.print('+');
} else if (x == 0) {
System.out.print('0');
} else {
assert (x > 0);
}

control
//ex. of ____ flow invariant
switch(suit) {
case Suit.CLUBS: //
break;
case Suit.DIAMONDS: //
break;
default:
assert false: 'Unknown';
break;
}

class
A _____ invariant is one that an object must satisfy in order to be a valid member of a class

class
//ex. of ____ invariant
public class PersonClassInvariant {
String name;
String son;
int age;
private void checkAge() {
assert age >= 18 && age < 150;
}
public void changeName(String fname) {
checkAge();
name=fname;
}
}

ea
//turn on assertions
java -__ MyProgram

LocalDate
Questions that you can answer with _______:
(1) Is it in the future or past?
(2) Is it in a leap year?
(3) What day of the week is it?
(4) What is the day a month from now?
(5) What is the date next Tuesday?

LocalTime
Questions that you can answer with _______:
(1) When is my lunch time?
(2) Is lunch time in the future or past?
(3) What is the time 1 hour 15 minutes from now?
(4) How many minutes until lunch time?
(5) How many hours until bedtime?
(6) How do I keep track of just the hours and minutes?

LocalDateTime
Questions you can answer the following questions with _______:
(1) When is the meeting with corporate?
(2) When does my flight leave?
(3) When does the course start?
(4) If I move the meeting to Friday, what is the date?
(5) If the course starts at 9 AM on Monday and ends at 5 PM on Friday, how many hours am I in class?

()
The three basic byte read methods are:
(1) int read__
(2) int read(byte[] buffer)
(3) read(byte[] buffer, int offset, int length)

byte[]
The three basic byte read methods are:
(1) int read()
(2) int read( ____ buffer)
(3) read(byte[] buffer, int offset, int length)

offset
The three basic byte read methods are:
(1) int read()
(2) int read( byte[] buffer)
(3) read(byte[] buffer, int _____, int length)

close
//terminate open stream
void ______();

available
//get bytes avail in stream
int _______();

skip
//discard n bytes
long ____(long n);

write
//3 byte write methods
void _(int c)
void _(byte[] buffer)
void _(byte[], int offSet, int length)

close
//auto closed in try-w-r
void _____();

flush
//force write to the stream
void _____();

+=
//count bytes read
while ((read = fis.read(b)) != -1) {
fos.write(b);
count __ read;
}

read
//3 basic read methods
int _()
int _(char[] cbuf)
int _(char[] chuff, int offset, int length)

write
//basic write
void _(int c)
void _(char[] cbuf)
void _(char[] cbuf, int offset, int length)
void _(String string)
void _(String string, int offset, int length)

new
//chain streams FileReader
//to BufferedFileReader
try (BufferedReader bufInput = ___ BufferedReader(__ FileReader(args[0]));

in
//chain a buffered reader
//to an input stream that
//takes the console input
try (BufferedReader in = new BufferedReader(new InputStreamReader(System.__)) {
...
}

subpath
A portion of a path can be obtained by creating a subpath using the _____ method:
//example
Path subpath(int beginIndex, int endIndex);

detects
Every Path method either: (1) ____ what to do when a symbolic link is encountered, or (2) Provides an option enabling you to configure the behavior
when a symbolic link is encountered

provides
Every Path method either: (1) detects what to do when a symbolic link is encountered, or (2) ____ an option enabling you to configure the behavior
when a symbolic link is encountered

isReadable
//verify read access to file
//using Files Class
_______(Path)

isWritable
//verify write access to file
//using Files Class
_______(Path)

isExecutable
//verify execute ability
//using Files Class
_______(Path)

isSameFile
//verify method tests to
//to see whether two paths
//point to the same file
______(Path, Path)

createFile
//create a file
Files._____(Path dir);

createDirectory
//create a directory
Files._____(Path dir);

createDirectories
//create directories that
//don/t exist, from top
//to bottom
Files.__(Paths.get('/home/foo/bar/example'));

deleteIfExists
//delete file/dir/link w/
//no exceptions
Files.___(path)

delete
//delete file/dir/link w/
//exceptions
Files.__(path)

copy
//replicate a file or dir
Files.__(source, target, REPLACE_EXISTING, NOFOLLOW_LINKS);

move
//change location of file/dir
Files.__(src, trg, REP_EX);

list
//get a list of all of the files
Files.__(Paths.get('.'))

walk
//walk a dir structure
Files.__(Paths.get('.'))

lines
//convert BufferedReader
//into a stream
bReader.____()

readAllLines
//load a file into an
//ArrayList
Files.___(file);

Executors
Implementing instances can be obtained with _____
//example
ExecutorService es = ____.newCachedThreadPool();

Callable
The ____ interface: (1) Defines a task submitted to an ExecutorService (2) Is similar in nature to Runnable, but can: Return a result using generics, throw a checked exception
//example
package java.util.concurrent;
public interface __<V> {
V call() throws Exception;
}

Future
The ___ interface is used to obtain the results from a Callable's V call() method
//example
__<V> ___ = es.submit(callable);
try {
V result = __.get();
} catch (ExecutionException|InterruptedException ex) {
}

this
Synchronized methods use the monitor for the ______ object
//example
synchronized(___) { }

deadlock
//below will cause _____
synchronized(obj1) {
synchronized(obj2) {
...
}
}
synchronized(obj2) {
synchronized(obj1) {
...
}
}

availableProcessor
//detect number of
//processors
int count = Runtime.getRuntime().__();

threaded
//single-_____ example
//1 Gig
int[] data = new int[10241024256];
for (int i = 0; i < data.length; i++) {
data[i] = ThreadLocalRandom.current().nextInt();
}
int max = Integer.MIN_VALUE;
for (int value: data) {
if (value > max) {
max = value;
}
}
System.out.println('Max value found:' + max);

RecursiveTask
//__ example
public class FindMaxTask extends ____<Integer> {
private final int threshold;
private final int[] myArray;
private int start;
private int end;
public FindMaxTask(int[] myArray, int start, int end, int threshold) {
// copy parameters to fields
}
protected Integer compute() {
// shown later
}
}

parallelStream
//Make parallel stream
double result = eList.____()

stateless
//mutate the ____ way
List<Employee> newList02 = new ArrayList<>();
newList02 = eList.parallelStream()
.filter(e -> e.getDept().equals('Eng'))
.collect(Collectors.toList());

stateful
//mutate the ______ way
//doesn't parallelize
List<Employee> newList01 = new ArrayList<>();
eList.parallelStream().filter(e -> e.getDept().equals('Eng'))
.forEach(e -> newList01.add(e));

associative
If the combining function is ______, reduction parallelized cleanly
//examples
sum, min, max, average

DriverManager
You can access them by following the sequence:
(1) Use the _______ class to obtain a reference to a Connection object by using the getConnection method
(2) Use the Connection object to obtain a reference to a Statement object through the createStatement method
(3) Use the Statement object to obtain an instance of a ResultSet through an executeQuery method

Statement
You can access them by following the sequence:
(1) Use the DriverManager class to obtain a reference to a Connection object by using the getConnection method
(2) Use the Connection object to obtain a reference to a _____ object through the createStatement method
(3) Use the Statement object to obtain an instance of a ResultSet through an executeQuery method

ResultSet
You can access them by following the sequence:
(1) Use the DriverManager class to obtain a reference to a Connection object by using the getConnection method
(2) Use the Connection object to obtain a reference to a Statement object through the createStatement method
(3) Use the Statement object to obtain an instance of a _____ through an executeQuery method

driver
//URL for a JDBC driver
jdbc:<___>:[subsubprotocol:][databaseName][;attribute=value]
//example
String url = 'jdbc:derby://localhost:1527/EmployeeDB';

subsubprotocol
//URL for a JDBC driver
jdbc:<driver>:[ _____:][databaseName][;attribute=value]
//example
String url = 'jdbc:derby://localhost:1527/EmployeeDB';

databaseName
//URL for a JDBC driver
jdbc:<driver>:[ subsubprotocol:][ _______ ][;attribute=value]
//example
String url = 'jdbc:derby://localhost:1527/EmployeeDB';

attribute
//URL for a JDBC driver
jdbc:<driver>:[subsubprotocol:][databaseName][;____=value]
//example
String url = 'jdbc:derby://localhost:1527/EmployeeDB';

wrapper
To execute SQL queries with JDBC, you must create a SQL query ____ object, an instance of the Statement object
//example
Statement stmt = con.createStatement();

ResultSet
//use the statement
//instance to execute
//SQL query
____ rs = stmt.executeQuery(query);

executeQuery
//use a ResultSet object
String query = 'SELECT  -  FROM Employee';
ResultSet rs = stmt.___(query);

ResultSet
Resources held by the _____ may not be released until garbage is collection, therefore, it is a good practice to explicitly close _______ objects when they are no longer needed

resources
//try-with-___
try (Connection con = DriverManager.getConnection(url, username, password);
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(query)){...}

PreparedStatement
____ is useful when you want to execute a SQL statement multiple times
//example
PreparedStatement pStmt = con.preparedStatement(query);