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[Ruby] Rails migration

1 minute read

It was my first time to touch Rails migration, so I’ll briefly write it down for a memorandum of study.

[Java] Java study memo 2 with Progate

1 minute read

Type story There seem to be various types of data. I thought about int and numbers, but to be exact, it is an integer. Numbers with a decimal point or less ...

[Ruby] About the programming language called Crystal

1 minute read

Introduction First of all, what is Crystal? However, to put it simply, it is a programming language designed to run programs at a speed similar to C using t...

[Ruby] About Ruby symbols

less than 1 minute read

I learned about the ruby symbol, so take a note. At first glance, a symbol looks like a string, but the computer treats it as an integer, so There is an adv...

[Java] About Java method binding

7 minute read

Today I’m going to write an article about Java method bindings. I’ve been studying Java and I wasn’t really aware of it, so I decided to organize it properl...

[Java] [Java] Generics class and generics method

1 minute read

Introduction I am using the generics that are familiar in List and Map, but when using generics for my own class, it may become ambiguous, so keep at least ...

[Java] [Java] Adapter pattern

1 minute read

Verification environment Eclipse Oxygen.3a Release (4.7.3a) Java8

[Java] [Apache POI] Corresponding Excel version

1 minute read

Content of this article When using Apache POI to read and write Excel in Java, the corresponding component types differed depending on the Excel version, an...