Mark Reinhold will come to Japan for a basic lecture at the next Java Day Tokyo! .. Registration site will open soon!
-@Davidbuckjp --How to fix JVM bugs
--JDK 9 released on September 21, 2017
Arraylist<String> list = new ArrayList<>();
Stream<String> stream = list.stream();
//Will come to call like this
var list = new new ArrayList<>();
var stream = = list.stream();
** Note that type inference is not dynamically typed !!! **
--Java emphasized readability over writeability --In the past, there were many line breaks --Var makes it shorter and easier to read. Only the declaration disappears. --Same for other languages C ++ ... auto, Scala ... var / val Go ...: =
--The influence of Field and method arguments is because it spans multiple files. Local variables are completed in one file. I don't want to see another file for type inference.
--There are various restrictions other than using var --Restrictions --Initialization is required --Array parentheses are not available --Low number declarations are prohibited --Array literal --null initialization --Poly expression that cannot be resolved
--Can be expressed in the Denotable types () language. -> Cannot be represented by java
var hogehoge = new Object() {
public void say(){~}
}
hogehoge.say();
--Reserved words? Keywords? --const and goto are reserved words but not keywords --Keywords ... expressions that mean something in the language --Reserved words ... can't be used --var cannot be used as a class or interface. Expected that there would be no class for lowercase var ... --Can be used as variable name or field name
int var = 1; ... ok
class var {
}... ng
var var = var();Compile passes!
--Released OPEN JDK style guide ――I'm writing when to use var
――How to use? Guidelines
var List = new ArrayList<>();
--There are few other new features of java10, because it is a short term --Garbage Collector Interface JIT, GC, HosSpotRuntime JIT and GC were involved. The JDK has separate GC and JIT interfaces --Can you use full GC with Parallel Full GC for G1 G1? --thread local hondshakes Each thread refers to itself There is no need to stop another thread when you want to stop one thread. --jacac -h ... You can create a header file at the same time as creating a class file. --Added character code of de_DE_EURO German, Euro --Heap Allocation on Alternative Memory Device I want to use java for the memory here! --About JIT compiler
--Docker has more useful APIs --Disadvantages ... The cost of updating is high --Move and see with java 10 --Compile with Java 10 --Try using jdeps jdeprscan ... Check if you are using the internal API or deprecated API, and correct / update.
--See new feature JEP AppCDS @ OpenJDK --API changes See JSR --See the incompatible release --JEP310: Application Class Data Sharing Used for batches, running in large numbers in containers
--Full GC of G1 GC, which was a single thread execution, is parallelized ... Since it is a last resort, the situation of abuse itself is not good.
--Fixed the problem that the container was not recognized and the installation and operation was performed based on the number of CPUs and memory of the host-> Docker's memory is allocated only this, but the JVM is looking at the machine, so it is allocated It uses more memory! CPU is the same --The amount of system memory used for Hepi has been made flexible ... The notation has been changed to%. Easy to understand --Improved to be able to attach to processes on the container from the host
API
――What I thought I had to remember from now on --JVM, JIT compiler, GC ――I thought I had to remember the lambda expression --swing and AWT ――I could feel the confidence that the speakers are familiar with java. --Keep in mind that JDK10 cannot be released immediately, and that you should prepare for JDK11. --The story of finding a bug in Java JDK 10 ... Kishida Hatena --Production should use Long time Record after all --You can go to the bug report once you submit it to ML. ――If the threshold is high, you may want to tweet on Twitter. --java8-> 9 transfer is very incompatible. It seems that it became a compatible book of about 350p.
--There is such an HP JJUG (I first learned that it is Jay Jug) JJUG's HP
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