Why does array[idx++]+="a" increase idx once in Java 8 but twice in Java 9 and 10?

Why does array[idx++]+="a" increase idx once in Java 8 but twice in Java 9 and 10?

java java-8 javac java-9 java-10

java

Error:java: invalid source release: 8 in Intellij. What does it mean?

java intellij-idea compilation javac intellij-13

java

ant warning: "'includeantruntime' was not set"

java ant build javac build-tools

java

javac is not recognized as an internal or external command, operable program or batch file [closed]

java path environment-variables command-prompt javac

java

What is the difference between javac and the Eclipse compiler?

java eclipse javac

java

Why does a Java class compile differently with a blank line?

java compilation javac bytecode

java

In which language are the Java compiler and JVM written?

java jvm javac

java

Does the 'java' command compile Java programs?

java javac

java

javac option to compile all java files under a given directory recursively

java javac

java

javac not working in windows command prompt

java windows command-prompt javac

java

javac : command not found

java compilation centos javac

java

javac error: Class names are only accepted if annotation processing is explicitly requested

java javac

java

What is the --release flag in the Java 9 compiler?

java javac java-9

java

Is the creation of Java class files deterministic?

java compiler-construction javac

java

Java: How can I compile an entire directory structure of code ?

java compilation javac directory-structure

java