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→Concurrent collections
===With apt===
===With apt===
<nowiki>sudo apt-add-repository ppa:webupd8team/java
<nowiki>sudo apt-add-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer</nowiki>
Also ensure your JAVA_HOME variable has been set to:
Also ensure your JAVA_HOME variable has been set to:
</syntaxhighlight>
</syntaxhighlight>
== Concurrency ==
==Concurrency==
=== syncrhronized ===
===syncrhronized===
If there are multiple synchronized methods on an instance only one of them can be run by threads at one point in time<syntaxhighlight lang="java">
If there are multiple synchronized methods on an instance only one of them can be run by threads at one point in time<syntaxhighlight lang="java">
public class Counter {
public class Counter {
</syntaxhighlight>
</syntaxhighlight>
=== Locks ===
===Locks===
Solve the multiple synchronized methods on same instance (apart from ReentrantLock thre are TryLock and TryForLock)<syntaxhighlight lang="java">
Solve the multiple synchronized methods on same instance (apart from ReentrantLock thre are TryLock and TryForLock)<syntaxhighlight lang="java">
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantLock;
</syntaxhighlight>
</syntaxhighlight>
=== Atomic classes ===
===Atomic classes===
Solves the same problem as locks but for simple operators (AtomicInteger, AtomicBoolean, AtomicIntegerArray, AtomicLong, AtomicBoolean....)<syntaxhighlight lang="java">
Solves the same problem as locks but for simple operators (AtomicInteger, AtomicBoolean, AtomicIntegerArray, AtomicLong, AtomicBoolean....)<syntaxhighlight lang="java">
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicInteger;
</syntaxhighlight>
</syntaxhighlight>
=== Concurrent collections ===
===Concurrent collections===
<syntaxhighlight lang="java">
<syntaxhighlight lang="java">
import java.util.Hashtable;
import java.util.Hashtable;
</syntaxhighlight>
</syntaxhighlight>
=== CopyOnWriteArrayList ===
Expensive write, fast concurrent read, synchronized writes, free reads. <syntaxhighlight lang="java">
import java.utils.List;
import java.util.concurrent.CopyOnWriteArrayList;
public class CopyOnWriteArrayListRunner {
List<String> list = new CopyOnWriteArrayList<>();
// Threads -3
list.add("Ant");
list.add("Bat");
list.add("Cat");
// Threads - 10000
for (String element:list){
System.out.println(element);
}
}
</syntaxhighlight><br />
==Eclipse shortcuts==
==Eclipse shortcuts==
Ctrl + Space → Autocomplete.<br />
Ctrl + Space → Autocomplete.<br />