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When you first enter the Java pit, there are so many versions of Java. If you want to know what version you should download, you must first understand the difference between lts and non LTS

LTS and non LTS

Every time you go to the official website to download JDK, when you enter the Java se download page, you can see the three versions of JDK recommended on the page: the latest version of JDK, jdk11 and jdk8. In particular, one (LTS) is specially marked next to jdk11

LTS

According to the officially released description of Oracle Java se support roadmap:

For product versions after Java se 8, Oracle will designate a version every three years as the long term support (LTS) version, which is fully called long term support. According to the official plan, it usually provides five years of primary (Advanced) support after release and three years of extended (Extended) support after five years.

Java se 8 is the first lts version. At present, jdk11 released in September 2018 is also an lts version

From the Java platform group product management blog released on May 13, 2020, we can know that the commercial support and update of Java se 8 will be extended from March 2025 to at least December 2030 (longer than the support time of Java 11). Moreover, since December 2020, Oracle has indefinitely expanded the availability of updates for personal (non-commercial) use of Java se 8.

Non LTS

The non lts version is considered to be the cumulative implementation enhancement set of the latest lts version. Once new features are provided, any previous non lts version will be deemed to have been replaced. For example, Java se 9 is a non lts release and is immediately replaced by Java se 10 (including non LTS), which in turn is immediately replaced by Java se 11. However, Java se 11 is an lts release, so Oracle customers will receive Oracle premier support and regular updates even if Java se 12 is released.

↑ yes, the above paragraph is the original words in my Oracle Java se support roadmap.

Since 2017, Oracle has increased the release frequency of Java se to once every six months, mostly in March and September every year, and the support time of each version of non LTS is only six months.

What does that mean? Perhaps it would be more intuitive to go directly to the previous picture:

The so-called no harm without comparison. The non lts version is more like an experimental version. Each version will replace the previous version, just like the continuous optimization process of experiments until a version of lts appears. It must be a stable version that summarizes the advantages and disadvantages of previous versions of non LTS. LTS and lts cannot be replaced. Just like the relationship between jdk8 and jdk11, although jdk11 was launched after jdk8, it can be seen from the Java se support roadmap so far that jdk8 is obviously more popular so far.

Of course, this paragraph does not mean that you choose jdk8 between jdk11 and jdk8. On the contrary, due to the downward compatibility of Java, it can run in JDK 11 as long as you don't use methods or classes unique to JDK 8. Anyway, Java always provides free support for individuals (non-commercial). Personally, I think: if we use it for learning, it is naturally the latest lts version.

Java CPU and PSU

In short, the CPU is an odd version, such as Java se 8u201. PSU is an even version, such as Java se8u202. Is the odd version better or the even version better? This point has been made clear in the official data Java CPU and PSU version description. It repeatedly said that the official recommended the odd version.

There is no doubt that the authorities have said so, so don't tangle, odd version - choose it.

Differences between Java se, Java EE and Java ME

Java SE

Java SE (Java Platform Standard Edition) formerly known as J2SE, it allows the development and deployment of Java applications used in desktop, server, embedded environment and real-time environment. Java se includes classes that support the development of Java Web services and provides the basis for Java EE, such as Java language basis, JDBC operation, I / O operation, network communication and multi wire Process and other technologies.

Java EE

Java EE (Java Platform Enterprise Edition, Java Platform Enterprise Edition) formerly known as J2EE. The enterprise edition helps develop and deploy portable, robust, scalable and secure server-side java applications. Java EE is built on Java se. It provides Web services, component model, management and communication APIs, which can be used to implement enterprise level service-oriented architecture (service oriented architecture, SOA) and Web 2.0 applications.

Java ME

Java me (Java platform Micro Edition) was formerly known as J2ME, also known as k-java. Java ME provides a robust and flexible environment for applications running on mobile devices and embedded devices, such as mobile phones, PDAs, TV set-top boxes and printers.

Java ME includes flexible user interface, robust security model, rich built-in network protocols and online and offline applications that can be downloaded dynamically. Applications based on the Java ME specification can be written once for many devices, and can take advantage of the native functions of each device.

About Java se, Java EE and java me, it is the code farmer's ascension of heaven Zhi

That's all, 886

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