Lambda, Predicate

class Animal {
 boolean canHop = true;
 boolean canSwim;
 int x = 1;
 int y = 10;
}

interface CheckIface {
 int test1(Animal a);
}

//interface Predicate {
// boolean test(T t);
//}

class Solution {
 static final int i = 0;

 public static void main(String[] args) {
  Animal animal = new Animal();
  print1(animal, a -> {
   return a.x;
  });
  print1(animal, a -> a.y);
  print1(animal, a -> {
   return a.canHop ? 1 : 0;
  });

  print(animal, a -> a.canHop);
  print(animal, a -> a.canSwim);
 }

 static void print1(Animal a, CheckIface check) {
  if (check.test1(a) > 0)
   System.out.println("test " + check);
 }

 static void print(Animal a, Predicate<Animal> check) {
  if (check.test(a))
   System.out.println("test1 " + check);
 }

Class StringBuilder

Modifier and Type	Method and Description
StringBuilder	append(boolean b)
StringBuilder	append(char c)
StringBuilder	append(char[] str)
StringBuilder	append(char[] str, int offset, int len)
StringBuilder	append(CharSequence s)
StringBuilder	append(CharSequence s, int start, int end)
StringBuilder	append(double d)
StringBuilder	append(float f)
StringBuilder	append(int i)
StringBuilder	append(long lng)
StringBuilder	append(Object obj)
StringBuilder	append(String str)
StringBuilder	append(StringBuffer sb)
StringBuilder	appendCodePoint(int codePoint)
int	capacity()
char	charAt(int index)
int	codePointAt(int index)
int	codePointBefore(int index)
int	codePointCount(int beginIndex, int endIndex)
StringBuilder	delete(int start, int end)
StringBuilder	deleteCharAt(int index)
void	ensureCapacity(int minimumCapacity)
void	getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
int	indexOf(String str)
int	indexOf(String str, int fromIndex)
StringBuilder	insert(int offset, boolean b)
StringBuilder	insert(int offset, char c)
StringBuilder	insert(int offset, char[] str)
StringBuilder	insert(int index, char[] str, int offset, int len)
StringBuilder	insert(int dstOffset, CharSequence s)
StringBuilder	insert(int dstOffset, CharSequence s, int start, int end)
StringBuilder	insert(int offset, double d)
StringBuilder	insert(int offset, float f)
StringBuilder	insert(int offset, int i)
StringBuilder	insert(int offset, long l)
StringBuilder	insert(int offset, Object obj)
StringBuilder	insert(int offset, String str)
int	lastIndexOf(String str)
int	lastIndexOf(String str, int fromIndex)
int	length()
int	offsetByCodePoints(int index, int codePointOffset)
StringBuilder	replace(int start, int end, String str)
StringBuilder	reverse()
void	setCharAt(int index, char ch)
void	setLength(int newLength)
CharSequence	subSequence(int start, int end)
String	substring(int start)
String	substring(int start, int end)
String	toString()
void	trimToSize()

Class String

Modifier and Type	Method and Description
char	charAt(int index)
int	codePointAt(int index)
int	codePointBefore(int index)
int	codePointCount(int beginIndex, int endIndex)
int	compareTo(String anotherString)
int	compareToIgnoreCase(String str)
String	concat(String str)
boolean	contains(CharSequence s)
boolean	contentEquals(CharSequence cs)
boolean	contentEquals(StringBuffer sb)
static String	copyValueOf(char[] data) Equivalent to valueOf(char[]).
static String	copyValueOf(char[] data, int offset, int count) Equivalent to valueOf(char[], int, int).
boolean	endsWith(String suffix)
boolean	equals(Object anObject)
boolean	equalsIgnoreCase(String anotherString)
static String	format(Locale l, String format, Object... args) Returns a formatted string using the specified locale, format string, and arguments.
static String	format(String format, Object... args) Returns a formatted string using the specified format string and arguments.
byte[]	getBytes()
byte[]	getBytes(Charset charset)
void	getBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin) Deprecated.  This method does not properly convert characters into bytes. As of JDK 1.1, the preferred way to do this is via the getBytes() method, which uses the platform's default charset.
byte[]	getBytes(String charsetName)
void	getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
int	hashCode()
int	indexOf(int ch)
int	indexOf(int ch, int fromIndex)
int	indexOf(String str)
int	indexOf(String str, int fromIndex)
String	intern()
boolean	isEmpty()
static String	join(CharSequence delimiter, CharSequence... elements)
static String	join(CharSequence delimiter, Iterable<? extends CharSequence> elements)
int	lastIndexOf(int ch)
int	lastIndexOf(int ch, int fromIndex)
int	lastIndexOf(String str)
int	lastIndexOf(String str, int fromIndex)
int	length()
boolean	matches(String regex)
int	offsetByCodePoints(int index, int codePointOffset)
boolean	regionMatches(boolean ignoreCase, int toffset, String other, int ooffset, int len)
boolean	regionMatches(int toffset, String other, int ooffset, int len)
String	replace(char oldChar, char newChar)
String	replace(CharSequence target, CharSequence replacement)
String	replaceAll(String regex, String replacement)
String	replaceFirst(String regex, String replacement)
String[]	split(String regex)
String[]	split(String regex, int limit)
boolean	startsWith(String prefix)
boolean	startsWith(String prefix, int toffset)
CharSequence	subSequence(int beginIndex, int endIndex)
String	substring(int beginIndex)
String	substring(int beginIndex, int endIndex)
char[]	toCharArray()
String	toLowerCase()
String	toLowerCase(Locale locale)
String	toString()
String	toUpperCase()
String	toUpperCase(Locale locale)
String	trim()
static String	valueOf(boolean b) Returns the string representation of the boolean argument.
static String	valueOf(char c) Returns the string representation of the char argument.
static String	valueOf(char[] data) Returns the string representation of the char array argument.
static String	valueOf(char[] data, int offset, int count) Returns the string representation of a specific subarray of the char array argument.
static String	valueOf(double d) Returns the string representation of the double argument.
static String	valueOf(float f) Returns the string representation of the float argument.
static String	valueOf(int i) Returns the string representation of the int argument.
static String	valueOf(long l) Returns the string representation of the long argument.
static String	valueOf(Object obj) Returns the string representation of the Object argument.

Interface List

All Known Implementing Classes:

AbstractList, AbstractSequentialList, ArrayList, AttributeList, CopyOnWriteArrayList, LinkedList, RoleList, RoleUnresolvedList, Stack, Vector

Class ArrayList

All Implemented Interfaces:

Serializable, Cloneable, Iterable, Collection, List, RandomAccess

Direct Known Subclasses:

AttributeList, RoleList, RoleUnresolvedList

Collections.sort(aList);
aList.sort(null);
A null value indicates that the elements' natural ordering should be used
aList.sort((e1,e2) -> e2 - e1); //DESC

boolean	add(E e)
void	add(int index, E element)
boolean	addAll(Collection<? extends E> c)
boolean	addAll(int index, Collection<? extends E> c)
void	clear()
Object	clone()
boolean	contains(Object o)
void	ensureCapacity(int minCapacity)
void	forEach(Consumer<? super E> action)
E	get(int index)
int	indexOf(Object o)
boolean	isEmpty()
Iterator<E>	iterator()
int	lastIndexOf(Object o)
ListIterator<E>	listIterator()
ListIterator<E>	listIterator(int index)
E	remove(int index)
boolean	remove(Object o)
boolean	removeAll(Collection<?> c)
boolean	removeIf(Predicate<? super E> filter)
protected void	removeRange(int fromIndex, int toIndex)
void	replaceAll(UnaryOperator<E> operator)
boolean	retainAll(Collection<?> c)
E	set(int index, E element)
int	size()
void	sort(Comparator<? super E> c)
Spliterator<E>	spliterator()
List<E>	subList(int fromIndex, int toIndex)
Object[]	toArray()
<T> T[]	toArray(T[] a)
void	trimToSize()

Date & Time

https://docs.oracle.com/javase/tutorial/datetime/TOC.html

LocalDate today = LocalDate.now();

LocalDate dateOfBirth = LocalDate.of(2012, Month.MAY, 14);
LocalDate firstBirthday = dateOfBirth.plusYears(1); 

LocalTime thisSec;

for (;;) {
    thisSec = LocalTime.now();
    display(thisSec.getHour(), thisSec.getMinute(), thisSec.getSecond());
} 

System.out.printf("now: %s%n", LocalDateTime.now());

System.out.printf("Apr 15, 1994 @ 11:30am: %s%n",
                  LocalDateTime.of(1994, Month.APRIL, 15, 11, 30));

System.out.printf("now (from Instant): %s%n",
                  LocalDateTime.ofInstant(Instant.now(), ZoneId.systemDefault()));

System.out.printf("6 months from now: %s%n",
                  LocalDateTime.now().plusMonths(6));

System.out.printf("6 months ago: %s%n",
                  LocalDateTime.now().minusMonths(6));

DateTimeFormatter format = DateTimeFormatter.ofPattern("MMM d yyyy  hh:mm a");

LocalDateTime leaving = LocalDateTime.of(2013, Month.JULY, 20, 19, 30); 

LocalDate date = LocalDate.parse(in, DateTimeFormatter.BASIC_ISO_DATE);

    DateTimeFormatter formatter =
                      DateTimeFormatter.ofPattern("MMM d yyyy");
    LocalDate date = LocalDate.parse(input, formatter); 

Instant t1, t2;
...
long ns = Duration.between(t1, t2).toNanos();

Instant start;
...
Duration gap = Duration.ofSeconds(10);
Instant later = start.plus(gap);

LocalDate today = LocalDate.now();
LocalDate birthday = LocalDate.of(1960, Month.JANUARY, 1);

Period p = Period.between(birthday, today);
long p2 = ChronoUnit.DAYS.between(birthday, today);
System.out.println("You are " + p.getYears() + " years, " + p.getMonths() +
                   " months, and " + p.getDays() +
                   " days old. (" + p2 + " days total)");

The code produces output similar to the following:

You are 53 years, 4 months, and 29 days old. (19508 days total)

Prefix	Method Type	Use
of	static factory	Creates an instance where the factory is primarily validating the input parameters, not converting them.
from	static factory	Converts the input parameters to an instance of the target class, which may involve losing information from the input.
parse	static factory	Parses the input string to produce an instance of the target class.
format	instance	Uses the specified formatter to format the values in the temporal object to produce a string.
get	instance	Returns a part of the state of the target object.
is	instance	Queries the state of the target object.
with	instance	Returns a copy of the target object with one element changed; this is the immutable equivalent to a set method on a JavaBean.
plus	instance	Returns a copy of the target object with an amount of time added.
minus	instance	Returns a copy of the target object with an amount of time subtracted.
to	instance	Converts this object to another type.
at	instance	Combines this object with another.

https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html

All letters 'A' to 'Z' and 'a' to 'z' are reserved as pattern letters. The following pattern letters are defined:

  Symbol  Meaning                     Presentation      Examples
  ------  -------                     ------------      -------
   G       era                         text              AD; Anno Domini; A
   u       year                        year              2004; 04
   y       year-of-era                 year              2004; 04
   D       day-of-year                 number            189
   M/L     month-of-year               number/text       7; 07; Jul; July; J
   d       day-of-month                number            10

   Q/q     quarter-of-year             number/text       3; 03; Q3; 3rd quarter
   Y       week-based-year             year              1996; 96
   w       week-of-week-based-year     number            27
   W       week-of-month               number            4
   E       day-of-week                 text              Tue; Tuesday; T
   e/c     localized day-of-week       number/text       2; 02; Tue; Tuesday; T
   F       week-of-month               number            3

   a       am-pm-of-day                text              PM
   h       clock-hour-of-am-pm (1-12)  number            12
   K       hour-of-am-pm (0-11)        number            0
   k       clock-hour-of-am-pm (1-24)  number            0

   H       hour-of-day (0-23)          number            0
   m       minute-of-hour              number            30
   s       second-of-minute            number            55
   S       fraction-of-second          fraction          978
   A       milli-of-day                number            1234
   n       nano-of-second              number            987654321
   N       nano-of-day                 number            1234000000

   V       time-zone ID                zone-id           America/Los_Angeles; Z; -08:30
   z       time-zone name              zone-name         Pacific Standard Time; PST
   O       localized zone-offset       offset-O          GMT+8; GMT+08:00; UTC-08:00;
   X       zone-offset 'Z' for zero    offset-X          Z; -08; -0830; -08:30; -083015; -08:30:15;
   x       zone-offset                 offset-x          +0000; -08; -0830; -08:30; -083015; -08:30:15;
   Z       zone-offset                 offset-Z          +0000; -0800; -08:00;

   p       pad next                    pad modifier      1

   '       escape for text             delimiter
   ''      single quote                literal           '
   [       optional section start
   ]       optional section end
   #       reserved for future use
   {       reserved for future use
   }       reserved for future use