kotlin单例模式

package com.hgc.studykotlin

class TestSingle private constructor() {

    companion object {
        private val testSingle = TestSingle()
        fun getTestSingle(): TestSingle {
            return testSingle
        }
    }
}

class TestSingleT private constructor() {
    companion object {
        @Volatile
        private lateinit var testSingle: TestSingleT

        fun getTestSingleT(): TestSingleT {
            if (testSingle == null) {
                synchronized(TestSingle::class) {
                    if (testSingle == null) {
                        testSingle = TestSingleT()
                    }
                }
            }
            return testSingle
        }
    }
}