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
 

Java Collections

You can not sort TreeMap on values.

Key points about HashSet:
    HashSet stores elements in random-order
    Allows only unique element/objects with maximum limit of 1 null

Java Spring Boot MVC

mv application.properties application.yml
spring:
profiles:dev
server:
port:81
---
spring:
profiles:prod
server:
port:80

mvn clean package
java -jar -Dspring.profiles.active=dev target/initial-boot-app-0.0.1-SNAPSHOT.jar

Actuator:
https://www.linkedin.com/learning/spring-boot-essential-training/spring-boot-actuator
localhost:8080/env
/health
/mappings

/health
/metrics
/configprops
/env
/loggers
/mappings



Spring Security
https://www.linkedin.com/learning/spring-boot-essential-training/implementing-spring-security

spring.thymeleaf.cache=false

Java Stream API

Processing Data with Java SE 8 Streams, Part 1
https://www.oracle.com/technical-resources/articles/java/ma14-java-se-8-streams.html  

Part 2: Processing Data with Java SE 8 Streams
https://www.oracle.com/technical-resources/articles/java/architect-streams-pt2.html

Package java.util.stream 
https://docs.oracle.com/javase/8/docs/api/java/util/stream/package-summary.html

Interface Stream
https://docs.oracle.com/javase/8/docs/api/?java/util/stream/Stream.html

https://www.youtube.com/watch?v=t1-YZ6bF-g0
Intermediate operations:
filter
map
flatmap
sort (sorted?)
anyMatch
distinct
findFirst

skip

Terminal operations:
forEach
collect
reduce
count
min
max
summaryStatistics


Stream API,part 1 https://www.youtube.com/watch?v=O8oN4KSZEXE
 Intermediate operations:
filter
map
flatmap
peek
sorted
distinct
limit
skip

unordered
parallel
sequential

Terminal operations:
forEach, iterator
find[First|All]
[all|any|non]Match
reduction, collectors

Stream API,part 2 https://www.youtube.com/watch?v=i0Jr2l3jrDA

Java Spring Boot Tips

@PropertySource("classpath/application.properties") @Value("${app_props_key}") private String app_prop_val; https://www.linkedin.com/learning/spring-framework-in-depth/implement-aop-advice-before loggin.level.root=INFO logMethodCall() LOGGER.log(app method params

Java learn & certification

https://docs.oracle.com/javase/tutorial/extra/certification/index.html https://coderanch.com/c/certification 13 Free Java 8 Certification Online Mock Tests https://www.java67.com/2017/05/10-free-java-8-certification-sample-questions-OCAJP8-OCPJP8-Mock-Exams.html https://www.udemy.com/course/spring-boot-complete-guide-from-development-to-deployment/?LSNPUBID=JVFxdTr9V80&ranEAID=JVFxdTr9V80&ranMID=39197&ranSiteID=JVFxdTr9V80-s9R8rW3unDigzKT4CYcaOA https://javarevisited.blogspot.com/2016/12/5-tips-to-prepare-for-oracle-java-certifications-OCAJP-OCPJP-exams.html?m=1 https://dou.ua/lenta/articles/java-11-developer-1/

Java stuff

JSON viewer:
http://jsonviewer.stack.hu/
Parse JSON String to Object in Spring Boot App


Automation JS frameworks
https://dou.ua/lenta/articles/automation-js-frameworks/?from=nl&utm_source=20191022&utm_medium=email&utm_campaign=CM

SCRUM
http://scrumy.com

User Interface with Boostrap Learning Module Overview

BufferedReader, InputStream, BufferedInputStream: Overview

Use BufferedReader, BufferedInputStream in Java

HTML View to Controller to Service to DAO

HTML View to Controller to Service to DAO
Thymeleaf th:each and Boostrap list-group integrated

JUnit
Test Driven Design/BDD with Spring Boot Example
Test Driven Development with Spring Boot

Mockito 
Use Mockito in Spring Boot to Mock Test Object

Spring Boot essentials
https://www.youtube.com/playlist?list=PL73qvSDlAVVh4QHMkO2gM52deldy64n45
From Zero to Hero with Spring Boot - Brian Clozel

https://linuxize.com/post/install-mariadb-on-centos-7/

AMQP: Asynchronous messaging in Spring Boot applications 
https://www.linkedin.com/learning/spring-boot-essential-training/asynchronous-messaging-in-spring-boot-applications

  Spring Data in Spring Boot applications 

https://www.linkedin.com/learning/spring-boot-essential-training/spring-data-in-spring-boot-applications 

  Spring Security in Spring Boot applications 

https://www.linkedin.com/learning/spring-boot-essential-training/spring-security-in-spring-boot-applications

Java PWM monitor

How to Compile Java Programs into EXEs
https://www.youtube.com/watch?v=Mr_TdPuF-4g

How to use ADC in STM32F103C8 - Measuring Analog Voltage
https://circuitdigest.com/microcontroller-projects/how-to-use-adc-in-stm32f103c8-stm32-blue-pill-board

Programming STM32F103C8 Board using USB Port
https://circuitdigest.com/microcontroller-projects/programming-stm32f103c8-board-using-usb-port