https://spring.io/projects/spring-boot: Spring Boot (Pivotal Software, Inc.) 
public class org.springframework.boot.context.ContextIdApplicationContextInitializer implements org.springframework.context.ApplicationContextInitializer<org.springframework.context.ConfigurableApplicationContext>, org.springframework.core.Ordered
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.springframework.boot.context.ContextIdApplicationContextInitializer
  super_class: java.lang.Object
{
  private int order;
    descriptor: I
    flags: (0x0002) ACC_PRIVATE

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
         0: .line 38
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 41
            aload 0 /* this */
            ldc 2147483637
            putfield org.springframework.boot.context.ContextIdApplicationContextInitializer.order:I
         2: .line 38
            return
        end local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lorg/springframework/boot/context/ContextIdApplicationContextInitializer;

  public void setOrder(int);
    descriptor: (I)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
        start local 1 // int order
         0: .line 44
            aload 0 /* this */
            iload 1 /* order */
            putfield org.springframework.boot.context.ContextIdApplicationContextInitializer.order:I
         1: .line 45
            return
        end local 1 // int order
        end local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    2     0   this  Lorg/springframework/boot/context/ContextIdApplicationContextInitializer;
            0    2     1  order  I
    MethodParameters:
       Name  Flags
      order  

  public int getOrder();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
         0: .line 49
            aload 0 /* this */
            getfield org.springframework.boot.context.ContextIdApplicationContextInitializer.order:I
            ireturn
        end local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/springframework/boot/context/ContextIdApplicationContextInitializer;

  public void initialize(org.springframework.context.ConfigurableApplicationContext);
    descriptor: (Lorg/springframework/context/ConfigurableApplicationContext;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=2
        start local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
        start local 1 // org.springframework.context.ConfigurableApplicationContext applicationContext
         0: .line 54
            aload 0 /* this */
            aload 1 /* applicationContext */
            invokevirtual org.springframework.boot.context.ContextIdApplicationContextInitializer.getContextId:(Lorg/springframework/context/ConfigurableApplicationContext;)Lorg/springframework/boot/context/ContextIdApplicationContextInitializer$ContextId;
            astore 2 /* contextId */
        start local 2 // org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId contextId
         1: .line 55
            aload 1 /* applicationContext */
            aload 2 /* contextId */
            invokevirtual org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId.getId:()Ljava/lang/String;
            invokeinterface org.springframework.context.ConfigurableApplicationContext.setId:(Ljava/lang/String;)V
         2: .line 56
            aload 1 /* applicationContext */
            invokeinterface org.springframework.context.ConfigurableApplicationContext.getBeanFactory:()Lorg/springframework/beans/factory/config/ConfigurableListableBeanFactory;
            ldc Lorg/springframework/boot/context/ContextIdApplicationContextInitializer$ContextId;
            invokevirtual java.lang.Class.getName:()Ljava/lang/String;
            aload 2 /* contextId */
            invokeinterface org.springframework.beans.factory.config.ConfigurableListableBeanFactory.registerSingleton:(Ljava/lang/String;Ljava/lang/Object;)V
         3: .line 57
            return
        end local 2 // org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId contextId
        end local 1 // org.springframework.context.ConfigurableApplicationContext applicationContext
        end local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
      LocalVariableTable:
        Start  End  Slot                Name  Signature
            0    4     0                this  Lorg/springframework/boot/context/ContextIdApplicationContextInitializer;
            0    4     1  applicationContext  Lorg/springframework/context/ConfigurableApplicationContext;
            1    4     2           contextId  Lorg/springframework/boot/context/ContextIdApplicationContextInitializer$ContextId;
    MethodParameters:
                    Name  Flags
      applicationContext  

  private org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId getContextId(org.springframework.context.ConfigurableApplicationContext);
    descriptor: (Lorg/springframework/context/ConfigurableApplicationContext;)Lorg/springframework/boot/context/ContextIdApplicationContextInitializer$ContextId;
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=4, locals=3, args_size=2
        start local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
        start local 1 // org.springframework.context.ConfigurableApplicationContext applicationContext
         0: .line 60
            aload 1 /* applicationContext */
            invokeinterface org.springframework.context.ConfigurableApplicationContext.getParent:()Lorg/springframework/context/ApplicationContext;
            astore 2 /* parent */
        start local 2 // org.springframework.context.ApplicationContext parent
         1: .line 61
            aload 2 /* parent */
            ifnull 3
            aload 2 /* parent */
            ldc Lorg/springframework/boot/context/ContextIdApplicationContextInitializer$ContextId;
            invokevirtual java.lang.Class.getName:()Ljava/lang/String;
            invokeinterface org.springframework.context.ApplicationContext.containsBean:(Ljava/lang/String;)Z
            ifeq 3
         2: .line 62
            aload 2 /* parent */
            ldc Lorg/springframework/boot/context/ContextIdApplicationContextInitializer$ContextId;
            invokeinterface org.springframework.context.ApplicationContext.getBean:(Ljava/lang/Class;)Ljava/lang/Object;
            checkcast org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId
            invokevirtual org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId.createChildId:()Lorg/springframework/boot/context/ContextIdApplicationContextInitializer$ContextId;
            areturn
         3: .line 64
      StackMap locals: org.springframework.context.ApplicationContext
      StackMap stack:
            new org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId
            dup
            aload 0 /* this */
            aload 1 /* applicationContext */
            invokeinterface org.springframework.context.ConfigurableApplicationContext.getEnvironment:()Lorg/springframework/core/env/ConfigurableEnvironment;
            invokevirtual org.springframework.boot.context.ContextIdApplicationContextInitializer.getApplicationId:(Lorg/springframework/core/env/ConfigurableEnvironment;)Ljava/lang/String;
            invokespecial org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId.<init>:(Ljava/lang/String;)V
            areturn
        end local 2 // org.springframework.context.ApplicationContext parent
        end local 1 // org.springframework.context.ConfigurableApplicationContext applicationContext
        end local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
      LocalVariableTable:
        Start  End  Slot                Name  Signature
            0    4     0                this  Lorg/springframework/boot/context/ContextIdApplicationContextInitializer;
            0    4     1  applicationContext  Lorg/springframework/context/ConfigurableApplicationContext;
            1    4     2              parent  Lorg/springframework/context/ApplicationContext;
    MethodParameters:
                    Name  Flags
      applicationContext  

  private java.lang.String getApplicationId(org.springframework.core.env.ConfigurableEnvironment);
    descriptor: (Lorg/springframework/core/env/ConfigurableEnvironment;)Ljava/lang/String;
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=2, locals=3, args_size=2
        start local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
        start local 1 // org.springframework.core.env.ConfigurableEnvironment environment
         0: .line 68
            aload 1 /* environment */
            ldc "spring.application.name"
            invokeinterface org.springframework.core.env.ConfigurableEnvironment.getProperty:(Ljava/lang/String;)Ljava/lang/String;
            astore 2 /* name */
        start local 2 // java.lang.String name
         1: .line 69
            aload 2 /* name */
            invokestatic org.springframework.util.StringUtils.hasText:(Ljava/lang/String;)Z
            ifeq 2
            aload 2 /* name */
            goto 3
      StackMap locals: java.lang.String
      StackMap stack:
         2: ldc "application"
      StackMap locals:
      StackMap stack: java.lang.String
         3: areturn
        end local 2 // java.lang.String name
        end local 1 // org.springframework.core.env.ConfigurableEnvironment environment
        end local 0 // org.springframework.boot.context.ContextIdApplicationContextInitializer this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0    4     0         this  Lorg/springframework/boot/context/ContextIdApplicationContextInitializer;
            0    4     1  environment  Lorg/springframework/core/env/ConfigurableEnvironment;
            1    4     2         name  Ljava/lang/String;
    MethodParameters:
             Name  Flags
      environment  
}
Signature: Ljava/lang/Object;Lorg/springframework/context/ApplicationContextInitializer<Lorg/springframework/context/ConfigurableApplicationContext;>;Lorg/springframework/core/Ordered;
SourceFile: "ContextIdApplicationContextInitializer.java"
NestMembers:
  org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId
InnerClasses:
  ContextId = org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId of org.springframework.boot.context.ContextIdApplicationContextInitializer