Clever Geek Handbook

APIs worth finally upgrading from Java 8 for. Part 3

What are the reasons for migrating to new Java versions? Someone will do it because of the new language features such as switch



, text blocks or records . Someone will need interesting new features like modules or low-pause garbage collectors . Someone will do this simply because by updating the Java version, their program will become faster and will eat less memory . But there is one more, no less important reason. These are new APIs that will allow you to write less code and avoid wasting time searching for the desired functionality in external libraries. And in some cases they will make your code faster.







In the previous two parts, we have already covered 10 new APIs that appeared in Java 9 and later ( part 1 , part 2 ). Today we will look at 10 more.









one. Stream.toList()





Introduced in: Java 16



What is the most commonly used task Stream



in Java? Of course, for the transformation of lists: we have a list over which we need to perform some kind of transformation and return a new one. You have probably seen this pattern many times in your project:







List<T> targetList = sourceList
        .stream()
        //  
        .collect(Collectors.toList());


This is not to say that it collect(Collectors.toList())



is a very cumbersome construction, but still I want to write less code for such a frequent operation. And in Java 16, this became possible with a new method Stream.toList()



:







List<T> targetList = sourceList
        .stream()
        //  
        .toList();


- toList()



collect(Collectors.toList())



? ? , : toList()



, collect(Collectors.toList())



, , . (, ), collect(Collectors.toList())



toList()



.







Stream.toList()



, ! , Stream.toList()



Stream.toArray()



, , Spliterator



SIZED



. Collectors.toList()



ArrayList



, .







. : , , .. . Stream



, new ArrayList<>(sourceList)



List.copyOf(sourceList)



, :







JMH- 
import org.openjdk.jmh.annotations.*;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Thread)
public class ToList {

    @Param({"10", "100", "1000"})
    private int size;

    private List<Integer> sourceList;

    @Setup
    public void setup() {
        sourceList = IntStream
                .range(0, size)
                .boxed()
                .collect(Collectors.toList());
    }

    @Benchmark
    public List<Integer> newArrayList() {
        return new ArrayList<>(sourceList);
    }

    @Benchmark
    public List<Integer> toList() {
        return sourceList.stream().toList();
    }

    @Benchmark
    public List<Integer> copyOf() {
        return List.copyOf(sourceList);
    }

    @Benchmark
    public List<Integer> collectToList() {
        return sourceList.stream().collect(Collectors.toList());
    }

    @Benchmark
    public List<Integer> collectToUnmodifiableList() {
        return sourceList.stream().collect(Collectors.toUnmodifiableList());
    }
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


OpenJDK 64-Bit Server VM (build 16+36-2231, mixed mode, sharing)
Intel Core i5-9500 3.00GHZ
 : -f 3 -wi 3 -w 5 -i 5 -r 5 -t 6 -jvmArgs -XX:+UseParallelGC




, Stream.toList()



collect(Collectors.toList())



, List.copyOf()



! , List.copyOf()



requireNonNull



, null



-, Stream.toList()



null



. List.copyOf()



, null



, Stream



: Spliterator



, ReferencePipeline



..







, . , filter()



:







JMH- 
import org.openjdk.jmh.annotations.*;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Thread)
public class ToListFilter {

    @Param({"10", "100", "1000"})
    private int size;

    private List<Integer> sourceList;

    @Setup
    public void setup() {
        sourceList = IntStream
                .range(0, size)
                .boxed()
                .collect(Collectors.toList());
    }

    @Benchmark
    public List<Integer> toList() {
        return sourceList.stream().filter(i -> i % 2 == 0).toList();
    }

    @Benchmark
    public List<Integer> newArrayList() {
        var list = new ArrayList<Integer>();
        for (var i : sourceList) {
            if (i % 2 == 0) {
                list.add(i);
            }
        }
        return list;
    }

    @Benchmark
    public List<Integer> collectToList() {
        return sourceList.stream().filter(i -> i % 2 == 0).collect(Collectors.toList());
    }

    @Benchmark
    public List<Integer> collectToUnmodifiableList() {
        return sourceList.stream().filter(i -> i % 2 == 0).collect(Collectors.toUnmodifiableList());
    }
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


OpenJDK 64-Bit Server VM (build 16+36-2231, mixed mode, sharing)
Intel Core i5-9500 3.00GHZ
 : -f 3 -wi 3 -w 5 -i 5 -r 5 -t 6 -jvmArgs -XX:+UseParallelGC






! Stream.toList()



new ArrayList()



. ? , Stream.toArray()



SpinedBuffer



, , ArrayList



. , ( chunk ). SpinedBuffer



, 100 (Integer



0 99):









ArrayList



, 1.5 , , . ArrayList



add()



, SpinedBuffer



, . , , .







: Stream.toList()



, , collect(Collectors.toList())



. ( Collectors.toList()



, downstream Collector



Collector



'). , collect(Collectors.toCollection(ArrayList::new))



.









2. String



: formatted()



, stripIndent()



translateEscapes()





: Java 15



Java 15 – , :







String str = """
        ,
        !""";


:







String str = String.format("""
        ,
        %s!""", user);


, ? . , . String.formatted()



, String.format()



:







String str = """
        ,
        %s!""".formatted(user);


, , , , , -, ( ), -, .







, formatted()



:







String str = ", %s!".formatted(user);


, .









, Java 15 – String.stripIndent()



, . , hello.txt



:







    ,
    !


, stripIndent()



:







String str = Files.readString(Path.of("hello.txt")).stripIndent();
System.out.println(str);


:







,
!




, – String.translateEscapes()



. : .







, hello.txt:







,\n!
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


String str = Files.readString(Path.of("hello.txt")).translateEscapes();
System.out.println(str);


:







,
!




3. CharSequence.isEmpty()



, CharSequence.compare()



StringBuilder.compareTo()





: Java 15 / Java 11



, .







, Java 1.5 , , String



isEmpty()



. length()



:







if (str.length() != 0) {
    ...
}


, Java 1.6 String.isEmpty()



- :







if (!str.isEmpty()) {
    ...
}


, String



– CharSequence



( ), - , (, default



- ). , StringBuilder



length()



:







if (stringBuilder.length() != 0) {
    ...
}


14 - : Java 15, isEmpty()



String



, CharSequence



:







if (!stringBuilder.isEmpty()) {
    ...
}




CharSequence



. equals()



: ? : CharSequence



String



, , .







, Java 11, , CharSequence.compare()



:







if (CharSequence.compare(charSeq1, charSeq2) == 0) {
    ...
}


compare()



, .







Java 11 StringBuilder



Comparable



, StringBuilder



compareTo()



:







if (stringBuilder1.compareTo(stringBuilder2) == 0) {
    ...
}




4. Collectors.filtering()



Collectors.flatMapping()





: Java 9



Collectors.groupingBy()



? , :







record Movie(String title, String genre, double rating) {
}


, :







Stream<Movie> allMovies = Stream.of(
    new Movie("", "", 7.385),
    new Movie("", "", 7.974),
    new Movie(" 2", "", 8.312),
    new Movie(" ", "", 8.33),
    new Movie(" ", "", 8.619),
    new Movie("", "", 8.363),
    new Movie("", "", 7.699)
);

Map<String, List<Movie>> groups = allMovies.collect(
    Collectors.groupingBy(Movie::genre));

groups.forEach((genre, movies) -> {
    System.out.println(genre + ":");
    movies.forEach(movie ->
        System.out.printf("    %s: %.2f%n", movie.title(), movie.rating()));
});


:







:
    : 8.36
:
    : 7.39
    : 7.97
     2: 8.31
:
     : 8.33
     : 8.62
:
    : 7.70


, , , , 8. ? , Stream.filter()



:







Map<String, List<Movie>> groups = allMovies
    .filter(movie -> movie.rating() > 8)
    .collect(Collectors.groupingBy(Movie::genre));
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


:
    : 8.36
:
     2: 8.31
:
     : 8.33
     : 8.62


: , , 8. ? : Java, Collectors.filtering()



:







Map<String, List<Movie>> groups = allMovies.collect(
    Collectors.groupingBy(Movie::genre,
        Collectors.filtering(movie -> movie.rating() > 8,
            Collectors.toList())));

groups.forEach((genre, movies) -> {
    System.out.println(genre + ":");
    if (movies.isEmpty()) {
        System.out.println("    <    8 >");
    } else {
        movies.forEach(movie ->
            System.out.printf("    %s: %.2f%n", movie.title(), movie.rating()));
    }
});


groupingBy()



, :







:
    : 8.36
:
     2: 8.31
:
     : 8.33
     : 8.62
:
    <    8 >




. :







record Movie(String title, String genre, double rating, List<String> actors) {
}


:







Stream<Movie> allMovies = Stream.of(
    new Movie("", "", 7.385,
        List.of("", "", "")),
    new Movie("", "", 7.974,
        List.of("", "", "")),
    new Movie(" 2", "", 8.312,
        List.of("", "", "", "")),
    new Movie(" ", "", 8.33,
        List.of("", "")),
    new Movie(" ", "", 8.619,
        List.of("", "", "", "")),
    new Movie("", "", 8.363,
        List.of("", "")),
    new Movie("", "", 7.699,
        List.of("", ""))
);


groupingBy()



, Set



? Collectors.mapping()



:







Map<String, Set<List<String>>> groups = allMovies.collect(
    Collectors.groupingBy(Movie::genre,
        Collectors.mapping(Movie::actors, Collectors.toSet())));


, , . ? Collectors.flatMapping()



, , Java 9:







Map<String, Set<String>> groups = allMovies.collect(
    Collectors.groupingBy(Movie::genre,
        Collectors.flatMapping(movie -> movie.actors().stream(),
            Collectors.toSet())));


! , :







:
    
    
:
    
    
    
    
    
    
    
:
    
    
    
    
    
    
:


.









5. StackWalker





: Java 9



? , ? , :







public final class MyLogger {
    public static void log(String message) {
        System.out.println(message);
    }
}


, , , , log()



. Java 8 StackTraceElement[]



, , Thread.getStackTrace()



:







public static void log(String message) {
    StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
    StackTraceElement stackTraceElement = stackTrace[2];
    String msg = stackTraceElement.getClassName() + "."
               + stackTraceElement.getMethodName() + "("
               + stackTraceElement.getFileName() + ":"
               + stackTraceElement.getLineNumber() + ") "
               + message;
    System.out.println(msg);
}


, . , ( , ), JVM Java-. , . :







@Benchmark
public String stackTrace() {
    StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
    StackTraceElement stackTraceElement = stackTrace[2];
    return stackTraceElement.getClassName() + "."
         + stackTraceElement.getMethodName() + "("
         + stackTraceElement.getFileName() + ":"
         + stackTraceElement.getLineNumber() + ")";
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


OpenJDK 64-Bit Server VM (build 16+36-2231, mixed mode, sharing)
Intel Core i5-9500 3.00GHZ
 : -f 1 -wi 3 -w 3 -i 5 -r 5 -t 6
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


Benchmark          Mode  Cnt    Score   Error  Units
Stack.stackTrace   avgt    5  103,704 ? 1,123  us/op


104 ! ! ? : StackWalker



, Java 9. .







StackWalker



«» . , StackWalker



StackWalker.getInstance()



. StackWalker



. getInstance()



StackWalker



. .







, StackWalker



, :









. log()



:







public static void log(String message) {
    String msg = StackWalker
        .getInstance()
        .walk((Stream<StackFrame> frames) -> {
            StackFrame frame = frames.skip(2).findFirst().get();
            return frame.getClassName() + "."
                 + frame.getMethodName() + "("
                 + frame.getFileName() + ":"
                 + frame.getLineNumber() + ") "
                 + message;
        });
    System.out.println(msg);
}


StackWalker



:







@Benchmark
public String stackWalker() {
    return StackWalker
        .getInstance()
        .walk(frames -> {
            StackFrame frame = frames.skip(2).findFirst().get();
            return frame.getClassName() + "."
                 + frame.getMethodName() + "("
                 + frame.getFileName() + ":"
                 + frame.getLineNumber() + ")";
        });
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


OpenJDK 64-Bit Server VM (build 16+36-2231, mixed mode, sharing)
Intel Core i5-9500 3.00GHZ
 : -f 1 -wi 3 -w 3 -i 5 -r 5 -t 6
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    


Benchmark          Mode  Cnt    Score   Error  Units
Stack.stackTrace   avgt    5  103,704 ? 1,123  us/op
Stack.stackWalker  avgt    5    2,781 ? 0,156  us/op


37 ! . , 2.8 , , .







StackWalker.walk()



Stream



, : , , -. , «», :







package org.mylogger;

public final class MyLogger {
    public enum Level {
        ERROR, WARN, INFO
    }

    public static void error(String message) {
        log(Level.ERROR, message);
    }

    public static void warn(String message) {
        log(Level.WARN, message);
    }

    public static void info(String message) {
        log(Level.INFO, message);
    }

    public static void log(Level level, String message) {
        ...
    }
}


frames.skip(2)



, log()



, error()



, warn()



, log()



, . – Stream.dropWhile()



:







public static void log(Level level, String message) {
    String msg = StackWalker
        .getInstance()
        .walk((Stream<StackFrame> frames) -> {
            StackFrame frame = frames
                .dropWhile(f -> f.getClassName().startsWith("org.mylogger"))
                .findFirst()
                .get();
            return level + " "
                 + frame.getClassName() + "."
                 + frame.getMethodName() + "("
                 + frame.getFileName() + ":"
                 + frame.getLineNumber() + ") "
                 + message;
        });
    System.out.println(msg);
}




StackWalker



?







, Java 9 . , classpath. – , . , org.example.mylib.internal



, , :







package org.example.mylib.internal;

public final class Handler {
    public static void handle() {
        ...
    }
}


Handler



, . , , ? , StackWalker.getCallerClass()



, :







package org.example.mylib.internal;

public final class Handler {
    public static void handle() {
        if (!StackWalker
            .getInstance(Option.RETAIN_CLASS_REFERENCE)
            .getCallerClass()
            .getPackageName()
            .startsWith("org.example.mylib.")) {
            throw new RuntimeException("Security error");
        }
        ...
    }
}


RETAIN_CLASS_REFERENCE



, Class . , Stream.walk()



, getCallerClass()



.









6. System.Logger





: Java 9



, API , Java 9. API : System.Logger



, System.LoggerFinder



System.Logger.Level



.







System.Logger



:







public final class Main {
    private static final Logger LOGGER = System.getLogger("");

    public static void main(String[] args)  {
        LOGGER.log(Level.ERROR, "Critical error!");
    }
}


:







. 17, 2021 6:24:57 PM org.example.Main main
SEVERE: Critical error!


System.Logger



– , , . , : , SLF4J – , Logback. Log4j API – Log4j Core. , System.Logger



– java.util.logging



, java.logging



.







SLF4J , , Log4j java.util.logging



. Log4j API SLF4J java.util.logging



. System.Logger



: , . java.util.logging



, - . , Log4j, :







<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.14.1</version> <!--       -->
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.14.1</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-jpl</artifactId>
    <version>2.14.1</version>
    <scope>runtime</scope>
</dependency>


: , log4j-jpl



classpath, . Java ServiceLoader



LoggerFinder



Log4jSystemLoggerFinder



Log4j:







18:24:57.941 [main] ERROR  - Critical error!


java.logging



JRE/JDK, ( java.util.logging



).







, System.Logger



SLF4J/Logback . – , SLF4J . GitHub . Log4j – .







System.Logger



:







LOGGER.log(Level.INFO, "Information");
LOGGER.log(Level.DEBUG, "Sum of {} and {} is {}:", 2, 3, 2+3);
LOGGER.log(Level.TRACE, () -> "Lazy message");
LOGGER.log(Level.ERROR, "Log exception", new Exception());




7. Lookup.defineHiddenClass()





: Java 15



MethodHandles.Lookup.defineClass()



, , . , : , , ( ). , . Java 15 , .







Lookup.defineHiddenClass()



. Unsafe.defineAnonymousClass()



, , . Unsafe.defineAnonymousClass()



Java 15 deprecated for removal.







:







  • . .
  • . , ( Class.forName()



    , ClassLoader.loadClass()



    , ClassLoader.findLoadedClass()



    ..). - < ->/<suffix>



    (, org.example.Temp/0x0000000800cb8000



    ).
  • , , , Class



    ( , , ClassOption.STRONG



    defineHiddenClass()



    ).
  • , -XX:+UnlockDiagnosticVMOptions -XX:+ShowHiddenFrames



    .


, , . :







jshell> Runnable runnable = () -> {}
runnable ==> $Lambda$26/0x0000000800c0aa00@443b7951

jshell> runnable.getClass().isHidden()
$2 ==> true




« ». int



'. javac, ByteBuddy.







- :







byte[] bytes = new ByteBuddy()
        .subclass(Object.class)
        .name("org.example.Temp")
        .defineMethod("sum", int.class, Modifier.PUBLIC)
        .withParameters(int.class, int.class)
        .intercept(new Implementation.Simple(
                MethodVariableAccess.INTEGER.loadFrom(1),
                MethodVariableAccess.INTEGER.loadFrom(2),
                Addition.INTEGER,
                MethodReturn.INTEGER))
        .make()
        .getBytes();


, -:







package org.example;
public class Temp {
    public int sum(int x, int y) {
        return x + y;
    }
}


, - , - :







Lookup lookup = MethodHandles
        .lookup()
        .defineHiddenClass(bytes, false);

//     MethodHandle  reflection
Object obj = lookup
        .findConstructor(lookup.lookupClass(), MethodType.methodType(void.class))
        .invoke();

MethodHandle sumHandle = lookup.findVirtual(lookup.lookupClass(), "sum",
        MethodType.methodType(int.class, int.class, int.class));

//   sum.   5
System.out.println(sumHandle.invoke(obj, 3, 2));


.









, , . :







Lookup lookup1 = MethodHandles.lookup().defineHiddenClass(bytes, false);
Lookup lookup2 = MethodHandles.lookup().defineHiddenClass(bytes, false);
Lookup lookup3 = MethodHandles.lookup().defineHiddenClass(bytes, false);
System.out.println(lookup1.lookupClass()); // class org.example.Temp/0x0000000800cb4000
System.out.println(lookup2.lookupClass()); // class org.example.Temp/0x0000000800cb4400
System.out.println(lookup3.lookupClass()); // class org.example.Temp/0x0000000800cb4800




8. Math





: Java 9 / Java 15



, , Java, :







int x = ...
int y = ...
long z = x * y;


Java, : int



– int



, , z



long



, . long



:







long z = (long) x * y;


, - . -, , , . -, , , . , . :







  int     long


Java 9 . Math.multiplyFull()



:







long z = Math.multiplyFull(x, y);




Java , , Java 8 Math



:







  • int toIntExact(long value)



  • int incrementExact(int a)



  • long incrementExact(long a)



  • int decrementExact(int a)



  • long decrementExact(long a)



  • int negateExact(int a)



  • long negateExact(long a)



  • int addExact(int x, int y)



  • long addExact(long x, long y)



  • int subtractExact(int x, int y)



  • long subtractExact(long x, long y)



  • int multiplyExact(int x, int y)



  • long multiplyExact(long x, long y)





, , – , - . ? , . , , , :







jshell> Math.abs(Integer.MIN_VALUE)
$1 ==> -2147483648


, – ? , , 2147483648 int



, . , Math.absExact()



, Java 15:







jshell> Math.absExact(Integer.MIN_VALUE)
|  Exception java.lang.ArithmeticException: Overflow to represent absolute value of Integer.MIN_VALUE
|        at Math.absExact (Math.java:1392)
|        at (#1:1)

jshell> Math.absExact(Long.MIN_VALUE)
|  Exception java.lang.ArithmeticException: Overflow to represent absolute value of Long.MIN_VALUE
|        at Math.absExact (Math.java:1438)
|        at (#2:1)




, , -11 3? ? :







jshell> -11 / 3
$1 ==> -3

jshell> -11 % 3
$2 ==> -2


, -11 = 3 * (-3) - 2



. , , Python, :







>>> -11 / 3
-4
>>> -11 % 3
1


- : -11 = 3 * (-4) + 1



. , : . Java , Python – . , Java -? Java 9 Math.floorDiv()



Math.floorMod()



:







jshell> Math.floorDiv(-11, 3)
$1 ==> -4

jshell> Math.floorMod(-11, 3)
$2 ==> 1




Java 9 Math.fma(float, float, float)



Math.fma(double, double, double)



, , a * b + c



, , :







jshell> Math.fma(2.99, 5.91, 7.1)
$1 ==> 24.7709

jshell> 2.99 * 5.91 + 7.1
$2 ==> 24.770900000000005




9. java.io.Serial





: Java 14



Java? , , Java-. :







public class Point {
    private static final long serialVersionUID = 1L;

    public int x;
    public int y;
}


Point



, :







var point = new Point();
point.x = 1;
point.y = 2;

var baos = new ByteArrayOutputStream();
try (var oos = new ObjectOutputStream(baos)) {
    oos.writeObject(point);
}
byte[] bytes = baos.toByteArray();




. , ? , Serializable



! ( serialVersionUID



, .)







:







public class Point implements Serializable {
    private static final long serialVersionUID = 1;

    public int x;
    public int y;
}


– : Serializable



, serialVersionUID



, .. , Java 14 Serial



.







, :







public class Point implements Serializable {
    @Serial
    private static final long serialVersionUID = 1;
    ...
}


, , :







public class Point {
    @Serial // Annotated member is not a part of the serialization mechanism
    private static final long serialVersionUID = 1;
    ...
}


:







public class Point implements Serializable {
    @Serial // Annotated member is not a part of the serialization mechanism
    private static final int serialVersionUID = 1;
    ...
}


, : serialVersionUID



, serialPersistentFields



, writeObject()



, readObject()



..







, IntelliJ IDEA. JDK 16 -Xlint:serial



. , javac



:







> javac -Xlint:serial Point.java
Point.java:6: warning: [serial] serialVersionUID must be of type long in class Point
    private static final int serialVersionUID = 1;
                             ^


, Java 17.









10. Objects



: checkIndex()



, checkFromIndexSize()



, checkFromToIndex()





: Java 9 / Java 16



.







, , , , . :







private static void getAt(int index, int length) {
    if (index < 0) {
        throw new IllegalArgumentException("index < 0");
    }
    if (index >= length) {
        throw new IllegalArgumentException("index >= length");
    }
    ...
}


, , :







public final class PreconditionUtils {
    public static void checkIndex(int index, int length) {
        if (index < 0) {
            throw new IllegalArgumentException("index < 0");
        }
        if (index >= length) {
            throw new IllegalArgumentException("index >= length");
        }
    }
}




Java 9 , Objects



.







Objects.checkIndex()



, [0, length)



:







jshell> Objects.checkIndex(-3, 10)
|  Exception java.lang.IndexOutOfBoundsException: Index -3 out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckIndex (Preconditions.java:70)
|        at Preconditions.checkIndex (Preconditions.java:248)
|        at Objects.checkIndex (Objects.java:372)
|        at (#1:1)

jshell> Objects.checkIndex(10, 10)
|  Exception java.lang.IndexOutOfBoundsException: Index 10 out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckIndex (Preconditions.java:70)
|        at Preconditions.checkIndex (Preconditions.java:248)
|        at Objects.checkIndex (Objects.java:372)
|        at (#2:1)




Objects.checkFromIndexSize()



, [fromIndex, fromIndex + size)



[0, length)



:







jshell> Objects.checkFromIndexSize(3, 8, 10)
|  Exception java.lang.IndexOutOfBoundsException: Range [3, 3 + 8) out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckFromIndexSize (Preconditions.java:82)
|        at Preconditions.checkFromIndexSize (Preconditions.java:343)
|        at Objects.checkFromIndexSize (Objects.java:424)
|        at (#3:1)

jshell> Objects.checkFromIndexSize(-2, 8, 10)
|  Exception java.lang.IndexOutOfBoundsException: Range [-2, -2 + 8) out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckFromIndexSize (Preconditions.java:82)
|        at Preconditions.checkFromIndexSize (Preconditions.java:343)
|        at Objects.checkFromIndexSize (Objects.java:424)
|        at (#4:1)

jshell> Objects.checkFromIndexSize(3, -4, 10)
|  Exception java.lang.IndexOutOfBoundsException: Range [3, 3 + -4) out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckFromIndexSize (Preconditions.java:82)
|        at Preconditions.checkFromIndexSize (Preconditions.java:343)
|        at Objects.checkFromIndexSize (Objects.java:424)
|        at (#5:1)




, Objects.checkFromToIndex()



, [fromIndex, toIndex)



[0, length)



:







jshell> Objects.checkFromToIndex(3, 11, 10)
|  Exception java.lang.IndexOutOfBoundsException: Range [3, 11) out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckFromToIndex (Preconditions.java:76)
|        at Preconditions.checkFromToIndex (Preconditions.java:295)
|        at Objects.checkFromToIndex (Objects.java:398)
|        at (#6:1)

jshell> Objects.checkFromToIndex(-4, 8, 10)
|  Exception java.lang.IndexOutOfBoundsException: Range [-4, 8) out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckFromToIndex (Preconditions.java:76)
|        at Preconditions.checkFromToIndex (Preconditions.java:295)
|        at Objects.checkFromToIndex (Objects.java:398)
|        at (#7:1)

jshell> Objects.checkFromToIndex(6, 4, 10)
|  Exception java.lang.IndexOutOfBoundsException: Range [6, 4) out of bounds for length 10
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckFromToIndex (Preconditions.java:76)
|        at Preconditions.checkFromToIndex (Preconditions.java:295)
|        at Objects.checkFromToIndex (Objects.java:398)
|        at (#8:1)




, Java 16 long



:













10 API, Java 16, 9- . , Java. , Java , , (1, 2, 3, 4, 5, 6, 7, 8). Java 8 , .







...







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