https://freemarker.apache.org/: FreeMarker is a "template engine"; a generic tool to generate text output based on templates. (Apache Software Foundation) 
public class freemarker.cache.MergingTemplateConfigurationFactory extends freemarker.cache.TemplateConfigurationFactory
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: freemarker.cache.MergingTemplateConfigurationFactory
  super_class: freemarker.cache.TemplateConfigurationFactory
{
  private final freemarker.cache.TemplateConfigurationFactory[] templateConfigurationFactories;
    descriptor: [Lfreemarker/cache/TemplateConfigurationFactory;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  public void <init>(freemarker.cache.TemplateConfigurationFactory[]);
    descriptor: ([Lfreemarker/cache/TemplateConfigurationFactory;)V
    flags: (0x0081) ACC_PUBLIC, ACC_VARARGS
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // freemarker.cache.MergingTemplateConfigurationFactory this
        start local 1 // freemarker.cache.TemplateConfigurationFactory[] templateConfigurationFactories
         0: .line 37
            aload 0 /* this */
            invokespecial freemarker.cache.TemplateConfigurationFactory.<init>:()V
         1: .line 38
            aload 0 /* this */
            aload 1 /* templateConfigurationFactories */
            putfield freemarker.cache.MergingTemplateConfigurationFactory.templateConfigurationFactories:[Lfreemarker/cache/TemplateConfigurationFactory;
         2: .line 39
            return
        end local 1 // freemarker.cache.TemplateConfigurationFactory[] templateConfigurationFactories
        end local 0 // freemarker.cache.MergingTemplateConfigurationFactory this
      LocalVariableTable:
        Start  End  Slot                            Name  Signature
            0    3     0                            this  Lfreemarker/cache/MergingTemplateConfigurationFactory;
            0    3     1  templateConfigurationFactories  [Lfreemarker/cache/TemplateConfigurationFactory;
    MethodParameters:
                                Name  Flags
      templateConfigurationFactories  

  public freemarker.core.TemplateConfiguration get(java.lang.String, java.lang.Object);
    descriptor: (Ljava/lang/String;Ljava/lang/Object;)Lfreemarker/core/TemplateConfiguration;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=11, args_size=3
        start local 0 // freemarker.cache.MergingTemplateConfigurationFactory this
        start local 1 // java.lang.String sourceName
        start local 2 // java.lang.Object templateSource
         0: .line 44
            aconst_null
            astore 3 /* mergedTC */
        start local 3 // freemarker.core.TemplateConfiguration mergedTC
         1: .line 45
            aconst_null
            astore 4 /* resultTC */
        start local 4 // freemarker.core.TemplateConfiguration resultTC
         2: .line 46
            aload 0 /* this */
            getfield freemarker.cache.MergingTemplateConfigurationFactory.templateConfigurationFactories:[Lfreemarker/cache/TemplateConfigurationFactory;
            dup
            astore 8
            arraylength
            istore 7
            iconst_0
            istore 6
            goto 21
      StackMap locals: freemarker.cache.MergingTemplateConfigurationFactory java.lang.String java.lang.Object freemarker.core.TemplateConfiguration freemarker.core.TemplateConfiguration top int int freemarker.cache.TemplateConfigurationFactory[]
      StackMap stack:
         3: aload 8
            iload 6
            aaload
            astore 5 /* tcf */
        start local 5 // freemarker.cache.TemplateConfigurationFactory tcf
         4: .line 47
            aload 5 /* tcf */
            aload 1 /* sourceName */
            aload 2 /* templateSource */
            invokevirtual freemarker.cache.TemplateConfigurationFactory.get:(Ljava/lang/String;Ljava/lang/Object;)Lfreemarker/core/TemplateConfiguration;
            astore 9 /* tc */
        start local 9 // freemarker.core.TemplateConfiguration tc
         5: .line 48
            aload 9 /* tc */
            ifnull 20
         6: .line 49
            aload 4 /* resultTC */
            ifnonnull 9
         7: .line 50
            aload 9 /* tc */
            astore 4 /* resultTC */
         8: .line 51
            goto 20
         9: .line 52
      StackMap locals: freemarker.cache.MergingTemplateConfigurationFactory java.lang.String java.lang.Object freemarker.core.TemplateConfiguration freemarker.core.TemplateConfiguration freemarker.cache.TemplateConfigurationFactory int int freemarker.cache.TemplateConfigurationFactory[] freemarker.core.TemplateConfiguration
      StackMap stack:
            aload 3 /* mergedTC */
            ifnonnull 19
        10: .line 53
            aload 0 /* this */
            invokevirtual freemarker.cache.MergingTemplateConfigurationFactory.getConfiguration:()Lfreemarker/template/Configuration;
            astore 10 /* cfg */
        start local 10 // freemarker.template.Configuration cfg
        11: .line 54
            aload 10 /* cfg */
            ifnonnull 15
        12: .line 55
            new java.lang.IllegalStateException
            dup
        13: .line 56
            ldc "The TemplateConfigurationFactory wasn't associated to a Configuration yet."
        14: .line 55
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/String;)V
            athrow
        15: .line 59
      StackMap locals: freemarker.template.Configuration
      StackMap stack:
            new freemarker.core.TemplateConfiguration
            dup
            invokespecial freemarker.core.TemplateConfiguration.<init>:()V
            astore 3 /* mergedTC */
        16: .line 60
            aload 3 /* mergedTC */
            aload 10 /* cfg */
            invokevirtual freemarker.core.TemplateConfiguration.setParentConfiguration:(Lfreemarker/template/Configuration;)V
        17: .line 61
            aload 3 /* mergedTC */
            aload 4 /* resultTC */
            invokevirtual freemarker.core.TemplateConfiguration.merge:(Lfreemarker/core/TemplateConfiguration;)V
        18: .line 62
            aload 3 /* mergedTC */
            astore 4 /* resultTC */
        end local 10 // freemarker.template.Configuration cfg
        19: .line 64
      StackMap locals:
      StackMap stack:
            aload 3 /* mergedTC */
            aload 9 /* tc */
            invokevirtual freemarker.core.TemplateConfiguration.merge:(Lfreemarker/core/TemplateConfiguration;)V
        end local 9 // freemarker.core.TemplateConfiguration tc
        end local 5 // freemarker.cache.TemplateConfigurationFactory tcf
        20: .line 46
      StackMap locals: freemarker.cache.MergingTemplateConfigurationFactory java.lang.String java.lang.Object freemarker.core.TemplateConfiguration freemarker.core.TemplateConfiguration top int int freemarker.cache.TemplateConfigurationFactory[]
      StackMap stack:
            iinc 6 1
      StackMap locals:
      StackMap stack:
        21: iload 6
            iload 7
            if_icmplt 3
        22: .line 68
            aload 4 /* resultTC */
            areturn
        end local 4 // freemarker.core.TemplateConfiguration resultTC
        end local 3 // freemarker.core.TemplateConfiguration mergedTC
        end local 2 // java.lang.Object templateSource
        end local 1 // java.lang.String sourceName
        end local 0 // freemarker.cache.MergingTemplateConfigurationFactory this
      LocalVariableTable:
        Start  End  Slot            Name  Signature
            0   23     0            this  Lfreemarker/cache/MergingTemplateConfigurationFactory;
            0   23     1      sourceName  Ljava/lang/String;
            0   23     2  templateSource  Ljava/lang/Object;
            1   23     3        mergedTC  Lfreemarker/core/TemplateConfiguration;
            2   23     4        resultTC  Lfreemarker/core/TemplateConfiguration;
            4   20     5             tcf  Lfreemarker/cache/TemplateConfigurationFactory;
            5   20     9              tc  Lfreemarker/core/TemplateConfiguration;
           11   19    10             cfg  Lfreemarker/template/Configuration;
    Exceptions:
      throws java.io.IOException, freemarker.cache.TemplateConfigurationFactoryException
    MethodParameters:
                Name  Flags
      sourceName      
      templateSource  

  protected void setConfigurationOfChildren(freemarker.template.Configuration);
    descriptor: (Lfreemarker/template/Configuration;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=2, locals=6, args_size=2
        start local 0 // freemarker.cache.MergingTemplateConfigurationFactory this
        start local 1 // freemarker.template.Configuration cfg
         0: .line 73
            aload 0 /* this */
            getfield freemarker.cache.MergingTemplateConfigurationFactory.templateConfigurationFactories:[Lfreemarker/cache/TemplateConfigurationFactory;
            dup
            astore 5
            arraylength
            istore 4
            iconst_0
            istore 3
            goto 4
      StackMap locals: freemarker.cache.MergingTemplateConfigurationFactory freemarker.template.Configuration top int int freemarker.cache.TemplateConfigurationFactory[]
      StackMap stack:
         1: aload 5
            iload 3
            aaload
            astore 2 /* templateConfigurationFactory */
        start local 2 // freemarker.cache.TemplateConfigurationFactory templateConfigurationFactory
         2: .line 74
            aload 2 /* templateConfigurationFactory */
            aload 1 /* cfg */
            invokevirtual freemarker.cache.TemplateConfigurationFactory.setConfiguration:(Lfreemarker/template/Configuration;)V
        end local 2 // freemarker.cache.TemplateConfigurationFactory templateConfigurationFactory
         3: .line 73
            iinc 3 1
      StackMap locals:
      StackMap stack:
         4: iload 3
            iload 4
            if_icmplt 1
         5: .line 76
            return
        end local 1 // freemarker.template.Configuration cfg
        end local 0 // freemarker.cache.MergingTemplateConfigurationFactory this
      LocalVariableTable:
        Start  End  Slot                          Name  Signature
            0    6     0                          this  Lfreemarker/cache/MergingTemplateConfigurationFactory;
            0    6     1                           cfg  Lfreemarker/template/Configuration;
            2    3     2  templateConfigurationFactory  Lfreemarker/cache/TemplateConfigurationFactory;
    MethodParameters:
      Name  Flags
      cfg   
}
SourceFile: "MergingTemplateConfigurationFactory.java"